Hello. I have a 95 blazer that when I hold the RPMs at 2000 in park. The throttle will go down to 1500 than back up to 2000. Does this every 2-3 seconds? It has 130k miles on it. I just bought it and these are the things I have done:
New fuel filter
New Cap and rotor
Fuel pressure check fine
Throttle position sensor.
Cleaned the egr valve and the carbon out of the intake.
Also like to mention that it runs fine when first started. Idle will stay at 2000rpm but after it warms up after 5 mins than it acts up.
I was wondering if it could be the Idle Air Control Valve. Cause I took it out and started the truck and it idled at like 3000rps but the surging stopped.
Any input will help. It has the aluminum manifold not the plastic ones like in 96 and up.

 

No one knows Anything.. wow

 

You might allow allittle time as most of us guys don't get paid for this and aren't on here 24-7..I would spray allittle carb cleaner around the plenum gasket and see if that effects the idle..I have seen many of there with bad gaskets that will affect the idle in the way you describe. Jerry

 

I suspect the IAC valve. Unplug your a/c compressor and see if the idle gets better. If so, it's a good bet that the IAC is the problem. Clean or replace it and clean the MAF sensor, also.

 

I did already tired the spray trick no difference. I seem many people look at this post and no one had a comment. I don't get paid as well but I only joined 2 weeks ago and helped 2 people already by looking in to there problem.my problem I never ran in to before. But thanks for tips.

 

Hmm. Funny you say unplug the ac. When I first got the truck it was unplugged. As for the maf this truck does not have one. At least not one that im use to seeing. Big square with wire mesh on air intake tube. I will unplug the ac and give it a try . Thanks

 

You're right, my error. The MAF wasn't used on these SUVs until the '96 model.