Pictures and diagram of engine sensor locations on the 3.8l V6 3800 engine in Chevy, Buick, Pontiac and Oldsmobile cars.. With the linkage at rest and the ignition on but engine off, adjust the screw until you see a value of .70-.71volts at idle. If you feel the idle speed is climbing with the adjustments you're making before reaching this voltage and not coming back down, adjust as high as you can go maintaining the desired stock idle speed.
Learn how to locate and adjust the idle screw on a 3800 V6 engine. This guide provides step-by-step instructions for proper idle adjustment.. The most common symptom of a dirty Idle Air Controller (IAC) is an erratic idle speed or surging when the car is stopped with the transmission in drive. Stalling may occur in some cases. Fig. 1 An Idle Air Controller. Note the red rubber O-ring seal. Sooner or later, mostly around 100k miles, many GM computer controlled engines develop trouble.