Iv had my cavy for about 2 months now and iv had a misfire since i bought it.
you can notice it most at idle !!! you hear the popping sound coming from the muffler.

I have replaced the spark plugs, and the coil, and i still have the problem !!

what else should i check before i bring it in to the shop.

It did put out a check engine code once, and it said random misfire on the computer

what should i do ??

Well lets see what can cause a misfire?

Fuel
-injector stuck open
- injector stuck open
- clogged injector

Ignition
-spark plug
- plug wire ( if on there)
- module
- coil

Engine
- low compression caused by bad rings

If its random it is usually coil related though

probalry few more things, those are the most common



- 2004 Cavalier - 124k, owned since new