1996LT1Z28

When I start my car for the first time in the morning when cold, the idle stays high (1000 rpm), then goes down to 800 rpms after the engine warms up.

Does this sound normal?

94Z28LS1toLT1

that sounds fine to me... mine does that too and will go to 900 and stay there perfect unless im wrong

Injuneer

You indicate you have an auto trans. Apparently you swapped the gears to have 3.42's. Stock idle programming fully warmed up is 650 RPM in neutral, and 550 RPM in gear. Stock tach can read 100 - 200 RPM above actual engine RPM. Put a scanner on the PCM to get the true idle speed.

The PCM is programmed to raise the idle on cold start, based on coolant temp. It can go as high as 1,200 RPM with sub-0°F temps. Idle speed will drop gradually as coolant warms up.

Injuneer

Can't compare. Programmed idle is higher for the M6.... 800 RPM fully warmed up.

94Z28LS1toLT1

lol didnt read his signature until now,when i start mine up it will idle like 900 or 1000 then after warm up will go to 800-850. thank you for the information