I have an 86 GT 5.0 and it surges like crazy. It will idle then start surging and sometimes stalls. What can I do to fix this problem.

 

Is the check engine light on? have you checked the idle air control? or is it a carb, im not up on the pre 87 stangs.

 

No, he definately has an FI unit unless it was converted. Come to think of it, my buddy had an 86 GT with the same problems, forgot how it was fixed.


Matt

 

Sounds like a bad TPS aka Throttle Position Sensor.

 

That would be what I would check first. I had mine go out and the car acted the same way.

 

yeah...there is a way to check your TPS voltage, also yank the IAC like they said...my 86s was very very dirty, and clean it out with some kind of carb cleaner..but away from the motor itself, or PB blaster...some kind of flammable checmical that is harsh...haha, but seriously, read up on TPS voltage for your year, it says what prongs to check with a volt meter...etc...what is good for idle voltage and whatnot.

 

Thanks for all the replies now I have to use all of the knowlege to get my stang up to par. Thanks and keep giving ideas.

 

When did they convert to mass air ve. speed density? I know a dirty mass air sensor will cause the surging problem. For some reason, I thought 85's had the speed density, then they switched to mass air in 86.

 

'89 was the first full year for Mass Air. I believe some California cars got it in mid '88 but it wasn't standard until '89.