96 Cavelier 2.4 Random Missfire

[Sunspot]

I am working on a 1996 Chevy Cavelier 2.4 that has a random missfire. Runs great 80% of the time, then all of a sudden starts kicking and bucking. I hook the scanner on it and watch the Missfire info datascreen. Drops cylinder 2 sometimes and then drops 3 sometimes, but never both at the same time. So far I have tried Plugs, Wire Boots, Coils, and Module. The only code that comes up is a missfire code. Does anyone have any ideas?

[deadBird]

First thing, check the compression on all cylinders. Then check the fuel injectors.

[Sunspot]

Fuel injectors are all working fine on the scanner and compression must be good, since most of the time the car runs great.

[deadBird]

Well don't actually test anything then.

[Sunspot]

good idea!

[jonsonton]

I think that would be a good idea. Lay off the scanner for a couple minutes and hook up a compression guage. You could have a sticking/bent valve or your head gasket could be leaking.
Sure your scanner might tell you the injectors are firing right by showing the injector pulse width, but does it show you if they are dirty or have unusually low resistance. I don't wanna sound like a dick, but sometimes you haave to diagnose things not just hook up a scanner.

[96Cavibutitspurple]

I would check the actual plastic piece that harnesses the two coils. that is what was wrong with my cavalier. look for small cracks in it.