What can cause a misfire other than ignition (plugs, wires and coils)

[PewterBird]

I am getting a missfire in cylinder 5. It intermettent. It only happens after the car has been running for awhile and then sits and cools all the way down. On the start up it starts right in.

My first step was to chang the plug but it still missfires in #5.

So I switched the 1st and 2nd coil to try to see if the misfire moves. It still missfires in #5. The coil is good.

So I switched the #3 and #5 wire, to check for a bad wire. It hasn't missfired yet. But its still cooling down.

If it still missfires in #5, what can cause a missfire other than the coils plugs and wires?

[98goldbird]

lots of things, that the dealership told me. Is anything leaking onto the the plug/wire/coil? You SURE its not the wire? (Same thing happened to me and it ended up being the wire). I would just call the dealership, and ask them what things cause a missfire. They'll list off a bunch of things. Westminister Buick Pontiac GMC is very helpful.

[camaroman1181]

ignition module... if they are going bad, they tend to act up as they heat up. after they cool down, they get better. especially since you changed the coils and teh miss stayed on that one cylinder. but it could also be the wires as well. how do the plugs look?

[robson]

same problem .... ingition module .... $158.99 .... just changed all the coils plugs n wires hopefully get it done tomorrow ... n if still same problem ... i'll suck it up and get the module

[robson]

well it must have been a bad plug one had a crack in it when i took it off soo maybe when it got hot it couldnt handle it ... ? ne luck with u

[V6viper]

I am going with the ICM as well. I replaced mine not one week ago. Get someone to take you up to Autozone and have it tested (don't buy it from them, though, o'reilly's is over $40 cheaper)

Remember, heat agitates voltage. So if it only does it after about 10-15 min of driving, it is something that throws sparks that takes a while to heat up.

That rules out the spark plugs. They get hot almost instantly.

Rules out the wires, too, they stay the same temperature pretty much from start.

It is more than likely the Ignition Control Module. Have it checked. :D