Cyclinder periodically deactivates and activates while driving

#1
Hello all,

I have an E36 1995 M3, 160,000 Miles of fun.

If i have a drive of about 40 minutes or more, my check engine light comes on and my car feels as if it lost 1 cylinder. I took the car in to the mechanic and he confirned my suspicion because the computer error was "Check cyclinder 4"...I took it to a few mechanics and each told me the computer was reporting a problem with cylinder 4.

What is strange is that the problem goes away..sometimes while i am driving, the engine will suddenly feel stronger and the check engine light turns off...This baffles my mechanic because he said a truely bad cylinder should not run normally...

Has anyone else encountered this behaviour before? What did u do to fix it?

Thanks for any info
 
#2
I've had similar problems with a wet ignition; have you detailed under the hood lately and gotten something wet?

It really sounds like an ignition problem (coil, sparkplug, plug wires). A possible way to test my theory would be to switch the ignition components from the cylinder with the problem to a different cylinder. If the problem moves to the new location, BINGO! Good luck.
 
#3
I agree - sounds like ignition, so check/swap the plug and coil as mentioned. If it stays with cylinder 4, then the fuel injector on that cylinder is the next likely suspect.
 


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