Syris71

My wifes 97 Cavalier is a 2.2l and has 180k on it. Out of the blue it started running very rough like its only running 2 or 3 cycl and stalls at stop signs. No check engine light. I replaced the fuel filter, plug wires, and plugs. Still the same. I aslo checked compression on all cycl and found them to be all ~160psi.
Sypmtoms seem very similar when her coil packs were bad 8 months ago and both coil packs were replaced. Can ignition coil packs go bad again that fast?

shawnvw

Sound like 1 of the coiils have gone bad.....usually have a 1 year parts warranty on it, you may have to pay for labour. Could also be the ign module, only giving power to one of the coils.

Syris71

Ok, I replaced both ignition coils and same problem. I also confirmed I am getting good spark to all 4 plugs. I noticed the brand new plugs are already black and soaty what does this indicate?
I also broke down and bought a good OBDII scanner. I am getting a P0300 code which is Multiple Cycl. Misfire. I checked for vacuum line leaks found none but not sure how to check for intake manifold or throttle bottle vacuum leaks. Could it maybe be a fuel pump or fuel reg or fuel injecter problem also?
I'm usually pretty good with engines but this one got me chasing my tail.

Dougleo

Take the EGR valve off and check to see if the pintle is stuck open with carbon. Very common with high mileage 2.2L's if it is, spray it out with carb cleaner and see if it helps.

They usually throw codes though, so check for vacuum leaks too.

Syris71

Took EGR valve off and pintle? not stuck open, but it felt a little sticky when I pushed open/close with a screwdriver. So I cleaned it out with carb spray and seems smooth now.
Engines still runs same though

Syris71

How do I check fuel pressure? There is no fuel test port on the fuel rail.

Syris71

Finally fixed this car
It was the timing chain, it jumped a few teeth throwing the mechanical timing off. I had replaced the chain set 80k ago but these cars use a plastic timining chain tensionor which seems to break down after 70k-90k

shawnvw

Glad to hear you fixed it!
Thanks for letting us know what that problem was

confused

thanks syris71 same problem timing chain tensioner broke again after 30k from first replacement so it was the last thing i checked couldent figure out how to proove it no balancer or timing tab pulled plugs and valve cover watched exaust valve close when piston was half way up on exaust stroke