My 89 Vandura 5.7 lit. idle's so high that when I put it into gear it slams pretty hard into gear. Anyone know how to adjust the idle or whatever I need to do to fix the problem?
Asked by joereedy30 Jan 22, 2015 at 02:34 PM about the 1989 GMC Vandura G3500 Extended
Question type: Maintenance & Repair
Idles high and I can't find any kind of an adjustment screw or anything to adjust. anyone
have any ideas?
3 Answers
Vacuum leak. Unmetered air entering throttle body will cause high idle. There is no adjustment. Or I don't know if a 1989 has a TPS, Throttle Position sensor, it probably does. The butterfly in the throttle body may not be closing all the way. Listen for a sucking sound, or hoses off, or nipples with nothing attached, all will cause a vacuum leak
7 people found this helpful.
Guru9D171W answered 4 years ago
Yes , same thing happened here, it was the vaccine line going into the throttle body, wasn’t hooked up