1985 Pontiac Fiero "high idle" problem

pontiac
sensors

#1

Basically, this has been an intermittent problem for years that has been increasingly more of a problem lately. What happens is, I will be driving and all of the sudden the car gets a surge of power and starts accelerating without me pushing the gas. I take it out of gear (manual transmission) and the car is idling at 2600 rpm. (that’s as high as it has gone but when it acts up it varies between 1300 and 2600). Sometimes it has no issues at all. I checked the engine code and I have an EGR code and a vehicle speed sensor code. I blocked off the vacuum line for the EGR and it still acted up, so I’m pretty sure it’s unrelated, but I was kind of on the edge with that one. The big clue for me was that it did not act up at all when I disconnected the vehicle speed sensor. But the car ran worse, was sluggish and it had no speedometer or odometer. So I replaced the vss and the car is still acting up. So my questions are: what occurs differently in the engine when it is at idle vs. when it is moving? and What is wrong with my car…other than my car?

Any advice or suggestions that you have to offer is very much appreciated. Thanks


#2

oh, I should have also mentioned that after you take the car out of gear and come to a complete stop, the engine speed gradually slows back down to normal.


#3

Get some choke cleaner & clean throttle plate on both sides & also clean the hole around the idle air control. Motorcycles For Sale