My 1998 S10 with the 2.2L started running rough with an intermittant miss. Most days it starts up and runs okay; others it misfires from slight to really rough. After running a while the misfire disappears. At first I thought it was happening when started cold; now it happens regardless of whether it is cold or hot. The shop installed new plugs and wire set, changed fuel and air filter, and new pvc. I get a code P0301 from the computer. Any suggestions would be greatly appreciated.

Tem

 

Are you getting fuel injector pulse at the fuel injector? Do you have a noid light?

 

I looked it up, P0301 is cylinder 1 misfire. The codes list appears to show that all cylinders have a misfire code so I think it narrowed it down for you already. Im reading a guide and It states you basicly check how your spark is going on cylinder 1 and possibly all of the cylinders. It could lead you down to a poorly firing cylinder and perhaps a bad coil pack (im assuming with the year) or maybe even a bad pcm, the guide points at a faulty injector if the spark is good. Oh! and I see a bad head gasket can start kicking these codes out, I know some guys who ran into this kind of stuff with a similar chevy motor before.

I know this post is old but It sounded like your on the road to alot of problems and I wanted to chime in if It wasnt too late.

 

You may want to check your injectors. If it isn't getting fuel it wont fire causing the comp to think you have a misfire.