Hello, I just want to ask if anyone knows what may be happening to my car.
When the car is in Park and running the idle goes up and down from 900-1100rpms, sometimes "like now" it drops down more low perhaps 800rpms or lower, enough to sound if it were to die but it does not , instead jumps back up to 1100rpms and hovers around 1000rpm "unsteady idle".
Im thinking it just may be a air/gas problem? maybe timing? I dunno, but the car has also been suffering from lower then normal MPG also

any ideas would be great, Lates

 

84.....hmm, computer-controlled Quadrajet carb?

Does the motor diesel at all when you shut it off? Check all the electrical connections with that carb...and if it has some kind of IAC/Air bypass valve, try disconnecting it and restarting. Also check that your base timing isnt too low. Typically surging is a symptom of either a rich a/f mixture, too low base timing, too low base idle setting, or a faulty sensor reading, typically TPS, thats causing the computer to keep playing with the IAC valve trying to achieve a stable idle but its too out of spec.

 

dopey me forgot to put that this is for a 1991 geo strom 1.6l, I thought I someone might know but I do beilve it may just need to have the timing done and the belts replaced.

 

palm bay close to miami?

 

get some carb cleaner and take the idle air control from the engine.un plug it.take it out.spray the idle air control until it is clean.spray the hole it goes into too.screw it back in and plug it back in.real simple.you will find that its covered with gunk.i will run smoother .promise. cam/am