Join Date: Apr 2010
57 Handyman is offline
Re: 1991 TBI Idle Loping
Have you solved your problem? If yes, what did you do? If not, then here's a different suggestion.
These TBI vehicles have a bunch of sensors which feed the ECM and could result in your situation. You've fiddled with two (IAC and TPS) which many of us would first suspect to be the culprit. At some point, you need to abandon remove and replace approach because it gets expensive.
My next suggestion is rebuild your TBI. I've done it and, for someone good with taking apart and putting things back together, it really isn't that difficult. I say rebuild rather than get a reman because, like carbs, they aren't exactly the same and, many times, are NOT interchangeable. A rebuild kit from NAPA will cost around $50 or so.
So, get a couple cans of carb cleaner, your tools, a couple of brushes, and a pan and have at it. It shouldn't take more than an hour. Be careful with the both fuel lines when reinstalling...you don't want to strip the threads.
Hopefully, rebuilding your TBI will solve the problem. If not, we'll discuss some other things to do.