1995 Jimmy Erratic idle

I have a 95` Jimmy (fuel injected )that is having some idling trouble. If I am not pressing the accelerator, the engine will rev up and down, like I am tapping on the gas pedal. The RPMs jump between about 500 to 1000. I cant find any vaccum leaks and I just replaced the air filter, the fuel filter, and the plugs. I also changed the oil and put some STP fuel system cleaner in the gas. I think it may be the TPS or something like that, because as long as I am pressing the accellerator, even if it is very lightly, the truck runs fine. The service engine soon light comes on too. It does this everytime I crank the truck, but not always right away. It does it when it is hot or cold. Any ideas?

First thing is to find out what code is stored...this may lead to or pinpoint your problem.

You may have an egr valve problem. I have a 95 jimmy and the same thing happened to my truck where the egr valve had to be replaced. I believe this is a common occurebce for this model. Good Luck taking care of this one.

try cleaning out you IAC valve take it out and clean it with an air compressor

I had the same problem, and like salleyne said, it was my EGR. just take the 2 bolts on it off, and pull it off and soak it in some carbeurator cleaner. the darn thing always gets carbon all up in it that gives it problems all the time. If this doesn't solve it, try replacing your PCV valve.

1.) Check the CPI injector for leaking.
2.) Clean and reinstall the EGR valve.

i had the same problem and i solved it cleaning the iac valve with carburator cleaner, good luck

Yea, in this situation it would work, remove, spray with TB cleaner, scrub with a toothbrush, rinse it with the cleaner, reinstall, reset your computer, restart the truck and put it in gear while stopped for 2 minutes so it can relearn the idle and you should be fine.