the check engine light came on, and its either steady or flashing. it spits out code p0300 which is multiple cylinder misfire. i changed all my spark plugs with ac delco's i bought at a chevy dealership. they said the're the same plugs that came with a 96 stock z28. it still spits out the same code and runs a little rough. what else could it be??

 

Could also be clogged injectors, bad plug wires, maybe some other fuel delivery problem. Did you try replacing the fuel filter?

 

Could also be the opti going bad. A bad pcm could also cause this. Don't think it is that, they are not known for that. I've also seen the water pump go bad and leak on to the opti and cause it to throw a code. Low idle will cause a multi miss fire code to throw. Just trying to give you some ideas in what it could be. Hope this helps.
John

 

Plug wires would be my first suspect.

 

i am getting the same code on my 97 and i have changed the opti, plugs and wires, and still has not fixed the problem. Every place i have gone to has told me the same thing, " well.. it could be several things, just have to change stuff till it is fixed" yea right.

 

Bandit97 In your case I would say it is a bad PCM. That sends the signal when to fire. If that don't send the signal at the right time it will throw that miss fire code.

 

any idea what a new pcm will run me and where the best place to get one at?