I just recently purchased this truck (77,000 miles) and have noticed that the RPM's at idle are right at 500. Every once in a while i can feel a little shake from the motor when at idle.
I put some Fuel Injector cleaner (Gumout) in it and did a long road trip to burn the whole tank through. That did not help any. I usually always run 93 octane in it.
My truck is stock, expect I just put 40 series Flowmasters on it yesterday.

Can anyone tell me what is causing my idle to be so low, and how to fix it?

01 Z71 ECSB, 5.3l

 

Sounds about right for a stock truck. My dad's stock 02 Tahoe idles right around 500.

 

That sounds about right.The idle is quite low between 500-600 rpm and is set in the PCM. To raise it you will need to have some one with tuning software do it. Unless it is stumbling badly you are probably OK.

You can try some sea foam in the intake manifold to see if that will help. Check the MAF and if it is dirty you can clean it with some electric contact cleaner without lubricant in it. Check the throttle plate and clean it with some carb cleaner or strong solvent if it has some oil on it from the PCV system. After a drive pull the vacuum hose off the fuel pressure regulator on the driver's side fuel rail and if there is fuel present then it needs to be changed. Other than that check that your plugs and wires are in good condition.

 

Cool - thanks for the info. I will give it all a good cleaning. Sounds like though that the idle is ok at 500. I had just read alot were people were talking about their idle being around 750.

 

People with an idle speed of 750 have a big cam installed and bump the idle up so that the engine will not stall out at stop signs and lights.