ccross

It's been doing this off and on for quite some time now, but with today its a constant thing. This is in regards to a '04 Cavalier 2.2l ecotech w/ 48,000 miles on it, 5 speed manual. Maintenance record is outstanding, oil changed every 3,000 miles with 15-40 Syntec, and really thats about it.

What it's doing is when I take it out of gear or push the clutch in, it drops from about 2,000 RPM (while driving) down to 3-500 then back up to 12-1300 then back down to 8-900 then back to idle at between 1000 to 1200. The only way I can keep this from happening is by keeping it in gear. When it drops to 300 rpm, it almost dies and everything dims. Any ideas?

Also my dash lights quit working. The rare times they do work, I cut the headlights on and I hear a slight chirp and they cut off. I had the dealership replace the cluster panel when it was under warranty due to a broken RPM gauge. Could I still hold them responsible? If not what can I do to fix it?

rkuelbs

It sounds like you have a sticking and/or slow reacting Idle Air Control valve. As the RPM drops past Idle Speed, the computer commands the IAC to open further to maintain RPM. As the IAC sticks, the computer just keeps telling it to open further, then when it finally unsticks, it ends up opening too far, and the computer has to compensate in the other direction.

You can try removing the IAC first and cleaning it well with Carb cleaner. Be sure to clean the passages in the throttle body also (and it won't hurt do a good throttle cleaning). If a good cleaning doesn't make your problem go away, it will be time to replace the IAC valve.

ccross

Thanks, referencing to my haynes manual, which section would I find the IAC and whatnot.

mnz24

The IAC is right on the front of the throttle body. I just took mine off today and cleaned as I am also having idle problems... I have a z24 5 speed manual and it happens when I shift into 1st gear and try taking off from a stop. The car loses power, drops rpms and almost dies before surging forward. I had an idle issue a couple months ago where my idle woudn't drop down. I ended up bringing it in and the shop reprogrammed my computer and it took care of it. I think I may just take my car back again...