cthomson21

Well first I'd like to say thanks for all the help that I have been given getting my car running. I have a slight problem that doesn't seem to be affecting anything, but it's getting quite annoying to me. When I crank my car it runs fine no problems what soever. The problem is that when it gets around 175 degrees the car seems to jerk slightly at idle almost like it has a miss. That is the only time it jerks or misses. When I hit the gas it runs fine. It doesn't have any codes, and the only thing I notice is that when its cold it idles between 800 and 900 rpms. Then wen it gets warm it appears to be idling at around 600 rpms. I really have no idea what it is. I assume its some kind of closed loop error. Should I start by unplugging an oxygen sensor? Any help would be awesome.

96capricemgr

When did you last clean the TB and IAC?

Is the miss parked in idle or at parking lot speeds in gear?

Injuneer

Your idle speed appears to be normal.

You have an auto trans, and the stock programming is 650rpm in neutral and 550rpm in gear, with the coolant fully warmed up. When you start a cold engine, the PCM raises the idle speed based on the coolant temp. The idle in gear will be elevated to 800rpm when coolant is 111*F or colder, and in neutral the idle will be increased to 900rpm at 111*F, 1,000rpm at 24*F and 1,200rpm at sub-0 temps.

Remember also that the stock tach typically reads 100-200rom higher than actual speed.

cthomson21

i have never cleaned either the tb or the iac......But since my idle speeds are right it has to me an intermitin miss fire of sometime right? Or maybe my car just shakes a lot? motor mount or something?