Rough idle slowly coming back
Thread Starter
Pro
Joined: Oct 2001
Posts: 554
Likes: 1
From: CA
Rough idle slowly coming back
Quick recap: got a ZZ4, left everything stock, except for 24# injectors. Car slowly started to idle rough, even almost stalling and then recovering. Pulled a code that it was running rich. I replaced the 3 month old O2 sensor about 3 weeks go and everthing seemed to be fine. But now it's slowly starting to idle rough again, and it's stalled twice after start up after I put it in gear. Drives fine when given throttle. I went to the archives and there are several reasons why you can run rich. Scorp posted that when you go bigger on the injectors you need to go down on the fuel pressure or get a chip. That's fine, but if I'm running rich, why would it take my O2 sensor a couple of weeks to realize it? Could it be something else? Also, I read that an exhaust leak could cause you to run rich. How do you look for or test for an exhaust leak? :cool:
Melting Slicks
Joined: Jun 2002
Posts: 2,168
Likes: 16
From: Phoenix AZ
Re: Rough idle slowly coming back (gpagaduan)
You should hook it up to a scanner. With the #24's in my car the fuel trim was at 108 blm's instead of 128, indicating that the ECM was subtracting fuel to keep the correct air/fuel mixture. However, the exhaust indication meter constantly toggles between rich and lean, so it appears the car is not really running rich. What does this mean? I'm not sure because my car still idles rough, too! I did send my custom chip in for programming changes for the #24's but haven't got it back yet.
I can probably be of more help regarding exhaust leaks. Jack up the car and start it cold. When it is cold is probably when it will leak most before the metal expands. You can also get up real close to listen and feel for leaks.
I can probably be of more help regarding exhaust leaks. Jack up the car and start it cold. When it is cold is probably when it will leak most before the metal expands. You can also get up real close to listen and feel for leaks.
