Searching For Idle - Check Engine Light Now On

[vz1610]

My '99 Automatic with 168,000 miles with no modifications has an idle issue that has been getting progressively worse. At first it would search for its idle after it warmed up. Lately the car will die if I do not feather the throttle at a light. The problem is worse if the AC is not on.

Today the check engine light came on so I grabbed the codes and hope someone will point me in the right direction to understand/correct this issue.

10-PCM:
• P1120 H
• 1220 H
• 1516 H
40-BCM:
• B0605 H
• B2592 H
• 2721 H
• 2723 H
AO-LDCM
• B2282 H
• 2284 H
• U1064H
A1 RDCM:
• B2283h
• B2285 h
• U1064 h
A6 SCM:
• B2860 H C
BO RFA:
• U1255 H

[Fixvet]

First of all....clear all of those codes, then drive your car for awhile then recheck the codes after that to see what is more current. Almost of your codes are "H" codes which means they are not current "C", but have been set before now. Maybe you knew that, but that's what the suffix letter means at the end of the code. Alot of times on a car like yours with alot of miles and age, the grounding points on the car need to be cleaned. Dirty grounds can cause alot of weird codes to be set. There is a ton of online info available on several Corvette forums on how to do that. Google for it.

Publish your codes again after you clear them and drive the car. You'll soon see a pattern or repeat codes on our DIC, then I'm sure you'll get some help on this forum.

You should clean your MAF sensor. If it's really dirty it can cause idle problems too. You may have some vacuum leaks causing this too.

[JohnnyDee]

Along with cleaning the MAF sensor, clean the Throttle body as well. It helped with my idle.

[vz1610]

Thanks, I will clear the codes and clean things up today.

[vz1610]

The throttle body was very dirty and the MAF sensor needed to be cleaned up as well. The idle is fixed so thank you very much!

I have cleared the codes and I will give them a check in a few days to see if anything pops up but thanks again for the suggestions.

[Fixvet]

Originally Posted by vz1610

The throttle body was very dirty and the MAF sensor needed to be cleaned up as well. The idle is fixed so thank you very much!

I have cleared the codes and I will give them a check in a few days to see if anything pops up but thanks again for the suggestions.

Don't use anything but CRC MAF cleaner, and CRC Throttle Body cleaner. There are several YouTube videos on this stuff. Do a google search.

These 2 CRC cleaners will not remove the coatings of the surfaces. Never use brake cleaner or Carb cleaner on these senstive parts.

[vz1610]

Good information and I did use the specific cleaners so I am in good shape!

[Fixvet]

Originally Posted by vz1610

Good information and I did use the specific cleaners so I am in good shape!

I didn't ask before, but I assumed your plugs and wires have been replaced by now?? If not, do it. It's a simple easy job.

[froggy47]

Originally Posted by Fixvet

I didn't ask before, but I assumed your plugs and wires have been replaced by now?? If not, do it. It's a simple easy job.

What he said.

[vz1610]

I replaced them at 98,000 miles so I am thinking about replacing them again soon.

Thanks for the feedback.