Intermittent Misfire
10-19-2015, 01:39 PM
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Intermittent Misfire So here is my dilemma, Ive got a swapped ls motor in my dodge with a 02 camaro harness and matching pcm. It has the most random engine misfire ever. I will be driving under 3k rpm and it will start to misfire, no cel, then just clear up randomly. I could drive it for an hour this way with no issues, doing multiple various RPM pulls then out of no where missfire for a few seconds and its good.
My tuner told me it was #7 doing it. So far this is what I have checked:
All wiring connections to the PCM, Injectors, coils, 02 sensors, crank sensor, cam sensor, everything good there.
A new PCM, coils, injectors, wires, plugs, cam sensor has been installed and the issue is still there. No vacuum leaks. TPS is reading fine. The harness has a good ground. The heads were checked, springs good, no bent valves, correct pushrod length, good compression.
I am at kind of a loss right now. Any help would be great. The only thing I havent changed were the 02's. But the truck will misfire the same way weather they are turned on or off. It was also tuned MAF only and speed density.
My tuner told me it was #7 doing it. So far this is what I have checked:
All wiring connections to the PCM, Injectors, coils, 02 sensors, crank sensor, cam sensor, everything good there.
A new PCM, coils, injectors, wires, plugs, cam sensor has been installed and the issue is still there. No vacuum leaks. TPS is reading fine. The harness has a good ground. The heads were checked, springs good, no bent valves, correct pushrod length, good compression.
I am at kind of a loss right now. Any help would be great. The only thing I havent changed were the 02's. But the truck will misfire the same way weather they are turned on or off. It was also tuned MAF only and speed density.
Last edited by 87DodgeD150; 10-19-2015 at 08:29 PM.
10-20-2015, 11:45 AM
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Wouldn't that cause erratic tach readings? Also what's the relearn process?
Edit:I looked up the relearn process. A buddy has the snap on scan tool and I'll see if it can do it.
Edit:I looked up the relearn process. A buddy has the snap on scan tool and I'll see if it can do it.
Last edited by 87DodgeD150; 10-20-2015 at 07:34 PM.
10-24-2015, 01:51 PM
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did you clean out the end of the fuelrail? it can collect dirt then it falls into the injector and clogs it up. swap your injector to a different location and see if the misfire moves. I had this happen on two different cars was very random and not easy to track down.
10-27-2015, 06:43 AM
#6
Check the rest of the fuel system as well. Buddy had a similar problem and turned out being the home applied tank liner coming off in pieces.
Intermittent fuel problems don't always throw a code, or if they do it can be misleading.
Intermittent fuel problems don't always throw a code, or if they do it can be misleading.