Misfire Under Load No Code

So any time it hits OD and the load is high, it'll miss HARD. If you find yourself in the unfortunate position of having a misfire in your Dodge Ram, understand that there are many reasons your vehicle might be acting up. It seems to do fine above 4000 rpm in any gear. I then had the misfire under light load with no CEL; replacing the coils and plugs fixed this. If there are no codes for a random. I have changed plugs, leads, pickups, ig box. Recently we completed a round trip from Dallas to Des Moines and back, and after the last fill-up in Oklahoma the car developed what feels like a misfire condition. going up long steep hills or any throttle opening over 40%. However, about a year later my left catalytic converter was toast and needed replacement. I believe in 93 you can still do it with a paperclip and count how many time the light flashes. For $175 per inj I decided no as the one replacement total of $475 was a budget breaker. At first glance this would appear to be a coil problem—coils are under the most stress under load. I know they had issues with coilpacks, but I phoned Hursts and they told me this car has already had one under warranty last year, and in January this year had an electronic ignition module an all. Hel There aren't any drips under the car, but there is a little bit of coolant loss over time. When I could not solve the misfire, I took the truck to Rick Hall's Auto Doctor in Tempe. Here are the four common types of misfire and how to check for the code P0302. First step to diagnosing a misfire is finding out what cylinders are misfiring, and when it occurs (under load, idle, when you let off the gas, etc). Let me start by saying the coils have already been replaced with the ECS red top coils two weeks back. P0302 Cylinder #2 Misfire. I had idle misfire on my '03 DOHC for at least 6 months and no codes, no pending. Its not the normal brick wall fuel cutoff, as it only does this for about a split second and the car resumes acceleration. Engine Misfire : Buick LaCrosse 3. Clio 182 misfire under light/medium load. try swapping plugs and wires from 4 and 6. The P0300 code means that a cylinder(s) is misfiring or is randomly misfiring. Misfire no code. 1 Pug 206, which over the last while (couple of months now) has developed a misfire at low revs (1500 - 3500) under load, it is also apparent when revved initally when not under load. Still makes no sense. Below is a picture of my Actron Pocket Scanner checking for engine misfire or other diagnostic trouble codes in the PCM on my vehicle. 7L Engine Miss. This code is set as a result of steady driving, it won't get set if you have your foot down or if you are accelerating too much. Injector pulse width will be longer than expected (significantly longer than 2. I had an issue with a misfire condition a few years back which showed the CEL, and it turns out the Bosch coil was bad so the dealer replaced it under warranty. Don't worry, you can still use your scanner & labscope to quickly and accurately identify the problem and fix it with confidence. my 94 won't let me. I had it Scan and there is no code also, nothing showed on the cylinder misfire calendar. Things I've changed. I've replaced the spark plugs with ne. Misfire Under Load And Low Revs When Warm Facebook There are no codes coming from the ECU aside from Code 5? But that seems to be the knock sensor, not sure if. I got on the gas a little and then it started dying, CEL flashing. But in 3rd gear trying to acellerate or trying to maintain speed, it would misfire like crazy. I have a 81 302 Ford small bolck in my P5b hotrod. Very Frustrated! Tried Everything. No help so took it to the Honda dealer. well I always had had a "random misfire"along with "x" cylinder code which is what prompted me to change the distributor and plugs, now it. At first glance this would appear to be a coil problem—coils are under the most stress under load. Intermittent Misfire on Acceleration 96 Dodge Neon was created by Brillon It has the SOHC engine. I have a 99 tahoe with a 5. So it was not a clean misfire, other things went wrong at the same time. I used the torque app and a bluetooth OBD scanner, and monitored the engine under load while driving. I back probe #6 injector and got signal from ECM when under load in gear and above 1900 RPM when i. The easiest way to find the faulty cylinder is to use a scanner that can read live data as you drive. Finally the engine light came on. If you hold that speed under load it continues. Typically an engine misfire under load, will be a problem with the ignition system, while low engine speed problems will be a vacuum, fuel management or compression issue. 2000 f150 5. If you have Ford Escape Misfire Codes read this. 5l GTDI misfire under load × Help us help you. Another common reason for misfire is spark plug gap. In diagnosing the misfire, some information is needed about the maintenance of the vehicle. Based on Illinois Environmental Protection Agency data test, the most common trouble codes that cause an OBD II plug-in emissions test failed on many vehicles and make the Check Engine light on would be fouled or a worn out catalytic converter. Ran fine at idle but under load would misfire. Idols 100% fine. The stumble/pulsation in this range starts *exactly* when the TGVs open, and fades away as soon as load increases. especially the large one under the top? No codes are showing for misfire, New plugs, cleaned throttle body and checked. Got home, plugs look clean, coils look good, cleaned EGR again to no avail. A misfire just means that the ECM has determined that that particular cylinder is slacking off, so to speak. Took it back to the mechanic and it showed a misfire on cylinder 7, replaced the plug which had a crack. Usuallly weak spark cause a misfire under a load,the compression increases when you open the throttle and can snuff out a weak spark --the cap and rotor can cause this even if they look perfect,but spark plug wires that are cracked,burnt from lying on an exhaust manifold or header will do the same,so can plugs that are fouled,or a weak ignition coil or pickup coil,sometimes the ignition module. Alice, Bob and Charlie are chatting together, and Charlie viciously launches an insult at Bob; but Bob, Master of Missing the Point, fires back, "I won't let you insult Alice like that!" Occasionally this will take an alternate form where. I am having a problem with a miss in the engine. Is anyone having problems with their 6. completely unpredictable. cotton filters esp the K&Ns are far less likley to cause contamination but i would never rule anything out, highflow foam filters are the most likely too, i know from a friend who has an alfa they wont use foam as it messes up the sensors so they all use K&N. inlet manifold seemed to be dirty with oil ? have ordered new crank case breather valve for tomorrow. There's a random misfire under load that appeared out of the blue at the exact same time the car quit on the freeway. Engine runs smooth every time it is started. I have performed top end cleaning on these engine's but never to address a misfire code. 7 horror tech random misfire 12-18-04 08:13 AM - Post# 577461 In response to mikhalljr I have a 98 Tahoe, 5. I could hardly get the car home and didn't think about code reading. 8 V10 with a misfire. I doubt that the. I run only OE parts and have replaced plugs/wires and air filter. Still threw a code 300,random misfire,couldnt track for sure which one it was. If the misfire problem has gone away and does not reoccur on the second or following trips, the OBD II system may erase the temporary misfire code and forget the entire episode. No more codes. I just drove a 160 mile trip with my car on Sunday, and it ran normally (slight hesitation due to a bad CCV). Learn how to run the codes, the ecm will give an idea of what is going wrong or what is ok, I read people say they ran the codes and got no codes, you should get an 11 code if the computer finds no sensors acting up. So it was not a clean misfire, other things went wrong at the same time. There should be no perceptable delay. Currently, motor is fine when not under any load. With the computer conected we monitored the live data and were recordeing most of the misfires in cylinder 6, 4, 2 with an occational misfire on 5. it does not show "check engine" lite or set a code. Intermittent misfires can be a real challenge to diagnose, so let's start with a steady misfire in one cylinder before moving on to intermittent misfires. New plugs, coils, fuel pump, filter in the last year All motorcraft parts except pump and filter. Ford Explorer, Aerostar. I've replaced the spark plugs with ne. (used motor with 40,000) All was good until I tried pushing the car and under heavy acceleration I got codes for catalytic conversion below efficiency and multiple cylinder misfire. Letting go of the gas a bit made the misfire stop and the flashing light disappear. I turn the truck off, allow it to sit for a few minutes, whip out the code scanner, only code that was there happens to be P0300. I had it at the local mechanic and he thought it was a plug lead so, I changed them. CYLINDER CONTRIBUTION Other Misfire Diagnostic Methods Other Misfire Diagnostic Methods The example below shows the upstream and downstream O 2 sensors for both banks of a Ford application with a V6 engine. They seem to occur for no apparent reason. P0351 means a misfire on cylinder #1. Turned out to be carbon deposit on the valve so it wouldn't close all the wayended up with blow-by which cooked the head. 2011 Ford Escape Can not duplicate, no code stored, there must not be a problem, etc etc. The misfire is only in certain RPM ranges, about 2300-2400, if I drop a gear and raise the RPM's it goes away. When I replaced the fuel regulator, that seemed to reduce the hesitation a little but when I replaced the TPS, that eliminated the problem altogether. Misfire at idle and under loadno codes Discussion in 'SN95 Cobras' started by Mentos, Aug 17, 2014. Another possible cause would be plugged exhaust (Catalytic converters and mufflers) can cause the engine to misfire or bog down under a load while trying to accelerate and may not flag a misfire code in the computer. The only mods done is a pod filter, FMIC, bigger fuel pump ( unknown brand or type), 3 inch from the dump and a manual boos controller which is wound right down to stock boost. While engine is running when you pull off lead 3 or 4 nothing happens but when you try do that on 1 or 2 it stalls. Truck runs great otherwise. Misfire Under Load I have an '02 WRX that misfires really bad under load. I lost sight of her so I pulled over. We had no codes recorded in the ECM but the fuel trims were way off. The problem has been on going for a couple months now. The only issues I've ever had was a bad wiper switch and brake light switch that would turn the brake lights on when it got cold over night. recently DENSO has made aftermarket coils to suit. When this occurrs with a hot engine the heat of the piston vaporizes the fuel. Can someone please help with what I should check next, I have a 1998 Chevy K1500 5. Engine would rock back and forth when misfiring. I got a 99 tahoe 5. 0 misfire under load NO smoke I have an 05 CC LB 4x4 176k I have owned it for a week, I haven't had a chance to get scanner or gauges yet and now she is acting up. 7 vortec that missfires on #4 cyl. Air filter is new & clean. Low RPM misfire from 1k-2k RPM's PLEEASE HELP!!! Frustrated. I did a little searching, and I saw that people recommended pulling the cam sensor to see if the problem went away. If flashing and misfire does not stop when lowering engine load, pull over immediately. Any advice would be appreciated. Ford Escape Misfire Codes. 2 L 385 hp Gas misfire will usually happen more under a load than at idle. Exterior; Autolamp automatic on/off headlamps; King Ranch F-150 fender badge; Vinyl upper door trim panels w/integral armrest, front/rear map pockets, courtesy lights; Heating, Ve. Since my vehicle is running good and there are no codes stored in the computer, this pocket scanner displays "no codes". I had it at the local mechanic and he thought it was a plug lead so, I changed them. you can hold brake and rev engine in "drive" and it will skip audiably (with magna-flo mufflers). Sometimes, while taking off from a stop or even accelerating from 20mph, the car will misfire/skip. The display will be blank if no other faults exist. I have addressed this here before, and long story short, I swapped the plugs around, swapped the injectors around, swapped the coils around, I cleaned the MAF, air box, injectors (Lucas/Chevron/premium). Finally the engine light came on. 0L acting like it is backfiring under load? Mine started doing this about 10K ago after I had the 30K service Misfire under load - Diesel Forum - TheDieselStop. If you find yourself in the unfortunate position of having a misfire in your Dodge Ram, understand that there are many reasons your vehicle might be acting up. Power is provided to the coils on the white/violet wire. Under load we have a misfire on cyl. Try hosing the coil down with some water and then power brake it and see if you can get it to misfire. It runs fine under load but I can feel an obvious misfire when idling and it stumbles around 1800 RPM with 1/8 throttle input and under. i can feel it. ok, i have a 2004 murano 3. Engine Misfire : Dodge Grand Caravan 3. Well, my 03 1ZZ-FE had a P0301 (cylinder 1) misfire that occured only under load, only well into the 5000 and above range. Intermittent rough running under load, especially uphill. Often times it'll miss with the A/C on at a light, or even idling as well. Its not the normal brick wall fuel cutoff, as it only does this for about a split second and the car resumes acceleration. Misfire Under Load I have an '02 WRX that misfires really bad under load. 7 vortec with multiple misfires under load/accelerating. Engine Misfire : Dodge Grand Caravan 3. When engine put under load, brakes on in drive giving a little gas, There is a definate hiss from the rear of the engine compartment. Batman: I see you're still carrying that dead weight around. Once the repair is complete, the same tool can clear the code, eliminating the "Check Engine" light. Cadillac cts misfire cylinder 6 causes 2007 CTS misfire at idle, no codes 800 x 600 · 129 kB · jpeg rough under low rpm load, misfire 1024 x 614 · 52 kB. I didn't drive it yesterday. The car currently has no power what so ever. May have figured out my misfire at idle issue. There is no MIL illuminated. I got home and shut it off and refired it with the hood up and it was still there. The "soft" misfire, often called a surge, is commonly associated with fuel related issues. That is not enough voltage to jump the spark plug gap and ignite the fuel/air mixture. When the miss/backfire happens, the CEL will come on with no stored code. Bought the car with 114k (stock) on it. Typically the ACT doesn't throw a code if unplugged, or if just laying in open air. My thinking is it has to be the injector, plug or COIL since its the only independent thing in the cylinder. the engine to misfire causing. i can feel it. 1996 GMC Sierra P300 Random Misfire: (cylinder 4 missfire or possibly cylinder 7 code I forget now) but I replaced all the O2 sensors and now it's decidedly. Some chunks of carbon are hanging onto the stems under the tulip. Last week started to run rough, code. It's been dead nuts reliable, never missing a beat. If the truck needs a little oomph to go up an incline the engine will seem to misfire until I hit the accelerator and it shifts out of overdrive and the rpm's increase, and the engine runs easier. Marlin Model 70 misfire My 1985 model 70 has been a flawless compainion until lately. When its goes into high RPM (above 3000) the back firing is so severe that some bucking is felt. 0L acting like it is backfiring under load? Mine started doing this about 10K ago after I had the 30K service Misfire under load - Diesel Forum - TheDieselStop. I just drove a 160 mile trip with my car on Sunday, and it ran normally (slight hesitation due to a bad CCV). Fix Ford Escape Misfire Codes. so i checked it with a tech2 and found it was there. I pull over, shut it down, wait a couple minutes, restart, and it's working fine. Well, my 03 1ZZ-FE had a P0301 (cylinder 1) misfire that occured only under load, only well into the 5000 and above range. 4L constant misfire fixed!!!! - Ok guys, this is a log of my misfire nightmare. Does pulling the choke out make the problem better or worse? If no different then the problem is most likely ignition. Start by checking for intake leaks, intake gaskets are a common caused of multi-cylinder misfiring. Try swapping coil #4 with coil #1. If feels to me, as the throttle body opens, that is what. So I was fucking around with the Clubsport today looking for the misfire. Engine would rock back and forth when misfiring. Plugs are new TR6s with. Part 1: This 1999 Ford Ranger had a misfire at idle up to 2,000 RPM. No other codes. 0) it gave me another p0300 code and had no power. I'm going to do a datalog under load to try to capture what is going on during the event and then send it to Tony at TIC and go from there. Finally, one day while driving to work, it misfired and the check engine light. I had the misfire of cylinder #1 code and they ended up replacing my head after several weeks of diagnosis. Another common reason for misfire is spark plug gap. Forums > Ford Ecoboost > Ford F150, Raptor and Tremor Ecoboost > Issues, Repairs, TSBs, Warranty and Recalls > TSB 13-8-1 Stumble / Misfire and DTC's 2011-2012 Ford F150 Ecoboost 3. Pull SPOUT Connector and time it Adjustment in Ford EFI Engines. Search My Stuff. So far Ive replaced; plugs, wires, cap n rotor, coil, egr valve, fuel filter, o2 sensors. Took it apart and hit the coils with a hair dryer and it worked fine. Only happens when accelerating lightly under load. I am unsure as to the possibility of stored codes on this one if the light has never come on. Engine would rock back and forth when misfiring. When I first started out I often got a Ka-Boom, rather than a simple Boom. A misfire under load complaint can usually be broken down into 2 categories. I will never fit it in with all the riding that I will do this summer. at idle warm (and even not so warm), and running down the road at low speed, i have what sounds like a 2 cyl misfire. 3 ms at idle for NA engine), and DTC code P0171 may be set. Finally, one day while driving to work, it misfired and the check engine light. With the computer conected we monitored the live data and were recordeing most of the misfires in cylinder 6, 4, 2 with an occational misfire on 5. Bad misfire under load. Sitting on the trailer, it revs and idles fine, but misfires under load in the water. I just drove a 160 mile trip with my car on Sunday, and it ran normally (slight hesitation due to a bad CCV). It's been dead nuts reliable, never missing a beat. The only issues I've ever had was a bad wiper switch and brake light switch that would turn the brake lights on when it got cold over night. Since the only definite way to diagnose this is with an oscilloscope, which few people have including mechanics, replacing old worn out parts is usually the easiest fix. Does pulling the choke out make the problem better or worse? If no different then the problem is most likely ignition. Still makes no sense. Come along on this mobile diagnostic call to diagnose a misfire on a 2008 F-150. We reported on a fix for the 2011 and 2012 Ford F-150 with misfire/running rough/intermittent stumble under hard acceleration during wet/humid/damp conditions. CCV most likely culprit. The Honda dealer diagnosed all four bad injectors and low pressure fuel filter. I have a 2007 Silverado classic With a 5. 8L: The check engine light will be on. Mercedes-Benz had many problems with these vehicles setting misfire. The steering wheel shakes, but feels transmission related to me. So it was not a clean misfire, other things went wrong at the same time. Suggestions appreciated. It ran smooth othertimes. 2011 Ford Escape Can not duplicate, no code stored, there must not be a problem, etc etc. It didn't happen when the truck was cold but would show up when it had warmed up. I did a fault code check. 8-liter with an automatic. Re: Misfire under load Kez, if you enlarge the pics the plugs are all the right type, the 'gap' on plug 2 looks massive! also if you enlarge the coil pack pic you can see the water ingress on two of the coils - my money is on water/fluid getting in. Based on Illinois Environmental Protection Agency data test, the most common trouble codes that cause an OBD II plug-in emissions test failed on many vehicles and make the Check Engine light on would be fouled or a worn out catalytic converter. If the misfire problem has gone away and does not reoccur on the second or following trips, the OBD II system may erase the temporary misfire code and forget the entire episode. 0L acting like it is backfiring under load? Mine started doing this about 10K ago after I had the 30K service Misfire under load - Diesel Forum - TheDieselStop. Basically just misfiring when accelerating and under load, flashing the engine light a few times then it's ok when up to speed. There is a sticky thing here on how to do it. 1999 F250 with a 2002 T444E motor. Rough Idle. On drive back from the dealer, my wife reported the misfire again occured on acceleration, with the check engine light flashing. com News & Notes. For a year and a half, I did the tune up & injector cleaning thingy to fix the "multiple misfire" or the "#6 misfire" code that would occur under load (steep grades-towing). Rough acceleration is a typical sign of that your engine is misfiring. you can hold brake and rev engine in "drive" and it will skip audiably (with magna-flo mufflers). 4 liter engine that was stalling at idle and had a surging condition at lower engine rpms. The CEL will go away if I turn the car off and restart. The Mystery of the Misfiring MINI. The misfire under load has always proved Login to read more. Sometimes it wont do it for a while, other times it will do it every start up for several days straight. So your question doesn't make sense! Code P0300 is Random misfire detected; Code P0301 is Misfire at cylinder 1. Misfire at 3000rpm under load I've got a phase 2 RB25DET and it feels like it hits fuel cut at about 3000rpm, but you can drive through it, and it seems fine above that. The "sharp" misfire, on the other hand, frequently relates to ignition problems. i cannot hear anything under load or. 0L engine because I have been encountering a intermittent misfire when pulling a hill under load. A good friend phoned me from King of the Hammers last year, sharing that his late (2004) TJ Wrangler 4. Below is a picture of my Actron Pocket Scanner checking for engine misfire or other diagnostic trouble codes in the PCM on my vehicle. I had a mechanic that works for a GM dealership to look at it. About 3 months ago she developed a miss. The car currently has no power what so ever. I have addressed this here before, and long story short, I swapped the plugs around, swapped the injectors around, swapped the coils around, I cleaned the MAF, air box, injectors (Lucas/Chevron/premium). On my way to a good stopping place (in gear but pretty much idling, under no boost, <1500RPM) the CEL stopped flashing and stayed constant. With no trailer, taking off in granny low, it had no problem. Hey guys, i've been searching and searching and have tried so many things, i'm at my witts end I just got a 2003 sc frontier, i have a flashing engine light under load on the highway, getting the p300 code. it regularly does short runs,15 mile or so but has done a couple of 200+mile runs since the first occurance of the misfire. Good luck and welcome to stangnet. org Over-advanced ignition timing can cause a misfire or buck and jerk under load. 8 - no codes/no check engine light Here's a quick video: YouTube Hit the throttle and it stutters, misfires, no power. Recently we came across a 2005 Ford F150 with a 5. Lean misfires tend to be more noticeable at idle or under light load. 2003 F250 5. This engine misfire didn't arrive only under load: It could as well show up at idle as when accelerating. Intermittent Misfire on Acceleration 96 Dodge Neon was created by Brillon It has the SOHC engine. After about 15 mins she showed up and said her bike would not stay running. Why anyone would look down the bore of a loaded rifle is beyond me. While driving to and from work, I ran a recorder (CRRecorders) which scans (and saves) at 2 second intervals looking for a drop in rpm etc. 02 sensors seem to be switching, (graphed them with scanner) I checked the injector seals all of them looked fine. The latest Tweets from Ethan Alexander (@Druidic_Misfire). Looks like a golf ball now. My name is David Gorth and I recently experienced an engine misfire problem which may of interest to some of the AutoTap users. It seems to do fine above 4000 rpm in any gear. The "sharp" misfire, on the other hand, frequently relates to ignition problems. I have performed top end cleaning on these engine's but never to address a misfire code. If the truck needs a little oomph to go up an incline the engine will seem to misfire until I hit the accelerator and it shifts out of overdrive and the rpm's increase, and the engine runs easier. Usually a secondary ignition (cap,wires, etc) will show up under load. Check pcv hose connections. Finally, what is that little box behind the air cleaner. I had the misfire of cylinder #1 code and they ended up replacing my head after several weeks of diagnosis. Especially if the problem is amplified under heavy throttle. Things have improved after replacing my plenum pan gasket but there is a slight shudder. They can all test good with a multimeter but still misfire under load. IF YOU HAVE A MISFIRE CODE ,PLEASE READ THIS!!! and it can happen under load and lead you to think that something far worse went wrong. for BOSCH it is about $350 for all six and for the DENSO ones expect to pay a lil more about $430 for all 6 how ever you can buy them individually but you will. A bad coil and bad condenser can cause high load misfire. Some chunks of carbon are hanging onto the stems under the tulip. The code also may be erased if no misfires are encountered under similar driving conditions during the next 40 drive cycles. FWIW, my '94 developed a small misfire around 60K miles when under light load or when starting from a stop. This is often misdiagnosed as torque converter shudder. since they are very close in the firing order pattern. my '02 misfires occasionally and produces associated odor. Typically an engine misfire under load, will be a problem with the ignition system, while low engine speed problems will be a vacuum, fuel management or compression issue. I hear a vacuum leak at the back of the engine. If the Check Engine Light comes on, you may find any of the following codes: P0171, P0174 Lean fuel condition codes; P0120 to P0124 Throttle position sensor codes. Certainly the shift map sucks then we load up the engine in overdrive which is really no different than diagnosing a misfire in a service bay by putting it in drive and giving it a little gas while holding the brakes. The code P0300 stands for random misfire. I'm getting a misfire code on cylinder 2. Got home, plugs look clean, coils look good, cleaned EGR again to no avail. I replaced it with a 2006 350 MPI engine with about 170 hours. Recently we completed a round trip from Dallas to Des Moines and back, and after the last fill-up in Oklahoma the car developed what feels like a misfire condition. I wasn't aware that BMW had misfire data in. Fix Ford Escape Misfire Codes. If the Check Engine Light comes on, you may find any of the following codes: P0171, P0174 Lean fuel condition codes; P0120 to P0124 Throttle position sensor codes. Rough Idle causing a Misfire Condition Case Study. The spark plug wires are cracking everywhere and I can sometimes hear them arching off of something You think this might have something to do with it? It runs perfect with no misfire at idle and when revved slowly but if you stomp the gass or put it in drive under it will misfire. It happens randomly but regularly. I'm a pushrod guy, not as knowledgeable with the mod motors. An engine that hesitates, stumbles or misfires when accelerating or when it is under load, is an engine that is either sucking too much air, not getting enough fuel, or misfiring. [Solved] Misfire under light load. Looks like a golf ball now. I had no CEL and the plugs looked fine. since they are very close in the firing order pattern. Search My Stuff. Misfire under load It does it when I'm accelerating, usually between 3 and 4000 rpm, or when going uphill. Pottering round town is fine. Miss occurs at 40 to 50 miles an hour under part throttle while the trans is still in overdrive. Check Engine Light Code P0302 Misfire Detection Monitor - Cylinder 2 Misfire Description: How does a P0302 code trigger the check engine light? This code will trigger the check engine light as follows: The misfire detection monitor, a software strategy built into the computer, is designed to detect an engine misfire. car is in open loop under WOT so it ignore the o2s. Further information from the customer indicated that the truck misfired the worse in drive, not overdrive, at light to normal cruise around 2000 rpm to 2500 rpm. Finally, one day while driving to work, it misfired and the check engine light. 0l vortec recently put out a random misfire code so i was told by a buddy of mine to try plugs and wires first, so i did replacing them with brand new Bosch plugs and a Bosch wires, that worked for all of a day then a very slight misfire came back, along with the blinking engine light, the code again was the Po300 random misfire code, i was told i can try new coil. It seems to do fine above 4000 rpm in any gear. CYLINDER CONTRIBUTION Other Misfire Diagnostic Methods Ignition Misfire Downstream O 2 Example The example below shows the upstream and downstream O 2 sensors for both banks of a Ford application with a V6 engine. Another common reason for misfire is spark plug gap. Ford Escape Misfire Codes. Is anyone having problems with their 6. I drove the car with the blower belt off to get it tuned and running good. I am stumped and have seen nothing on the internet relating to this!! Please help. Midget 1500/Weber Carb Runs great at all RPM in shop. It's worse under load and gets bad when it's wet out.