I've got an 87 fullsize Jimmy with a 350 tbi 4x4 700r4. The issue is that the idle rises and drops apon start up. Even after it's warmed up. When I'm driving around on the gas pedal, it's runs fine with no SES light, but when I'm coming up to a stop light and I release gas pedal, SES light comes on and when I come to the stop, idle is high... So in gear; idle is high. In park; idle rises and drops...Sometimes it's just fine with no idle issues. Has this ever happened to anyone? I'm hoping it isn't something costly and as simple as changing a vac line or sensor...

I'm new to this forum but like what I've seen and look forward to participating. Any help and advice would be greatly appreciated.*
Thanx.*

 

I would recommend a good throttle body cleaning. I like to remove the throttle body all together and clean it on the work bench to make sure that it is nice and clean. A gummed up IAC (idle air control) valve can cause the symptoms you are experiencing.

 

Good idea and thank u. I'll try that and post the outcome.

 

Ditto, you will see that black TBI unit turn silver and gold again.