IAC, idle issues 2000 Silverado 5.3

[Steve40th396]

I have no codes. Truck has over 300000 miles. Runs good with an intermittent idle issue where it goes up and down. Doesnt change much when AC is on.

Is there a way to test IAC with a meter?

I have checked plugs, wires, sprayed engine with cleaner looking for vacuum leaks, to see if idle changes. Air cleaner is good..

But no codes..

Have not checked fuel pressure. I will Monday.

Other than that, I want to check IAC if its good. Is there a Meter test to look for Ohms on the pins?

[David89GMC]

Have you checked the compression, or done a leak down test?

Sure, the engine is electronically controlled, but don't forget it's a mechanical device with a lot of time on it. What you're seeing is very possibly the computer trying to correct for low compression.

[Steve40th396]

I have not done a compression check. I will put that on the checklist of looking for vacuum leaks, ignition wires, plugs etc.. Its old, but not too old, just allot of miles. Mostly slow city miles to and from work..