Idle Speed / 1998 Olds 88

[Mark72]

Does anyone know what the idle speed should be of a 1998 Oldsmobile eighty-eight with the V6 3800 II engine? Mine runs great, smooth, no issues. But I notice it idles at 1000 RPM and wonder if that is normal for that engine or not? I can't find anything online when I google it as far as specs.

 

[Chris142]

Usually 600ish once warmed up.

 

[maxdustington]

IAC

 

[AZjeff]

So you bought it. Get a good deal?

 

[clinebarger]

GM doesn't print a idle specification, However......Here are the target idle speeds vs coolant temp in the calibration.

Make sure there are no vacuum leaks!

People like to monkey around with the Throttle Plate Stop Screw, Adjustment procedure......
*Using a Scan Tool or a DVOM on the Blue Wire at the TPS.......See if the closed throttle voltage is between @ .20-.75 Volts. (If the voltage is in spec, No adjustment is necessary.
*If voltage is Above .80vdc......Adjust the throttle plate screw 'til .75vdc is achieved.
*IF the throttle plate is now sticky.....Remove the throttle body & clean the bore around the plate (Remove MAF while cleaning!)
*Clean the IAC passages as well if throttle body removal is deemed necessary.

*****If the idle speed is now low & unstable.......
*Inspect the IAC wiring for broken wires, And stretched out Terminals.
*If no issues are found, Replace IAC Motor as they are cheap enough.

 

[eljefino]

You can exercise the idle speed motor by taking off the air intake tubing and covering its hole with your finger. Take your finger off, it should surge then recover. If it doesn't recover the passages can be blocked and/or the motor's dead.

 

[clinebarger]

You can't access the IAC bypass hole on a 3800.