Hmmm... everyone here seems to have a manual, but some poor fools like me have the auto LS. I was just wondering.. what is 'normal' idle rpm for an auto? I have a 95 auto LS at ~70k and I idle at 1.5rpms. Should I adjust the valve? I was planning to Seafoam it this weekend for the first time. Will that lower it? What to do first? Help a noob out.

 

look under the hood at the vacuum diagram for the specs on idle or search for it. 1.5 is definitly not the right idle it should be under 1,000rpm.

adjust it.
i dont see why seafoam would correct an idle problem.

theres a screw on the throttle body to adjust it.

 

It shouldn't idle like that for any more than a minute or two at startup, but that's it. If it idles like that every time you're at a stop, that's a big problem. See if you can find the idle air adjustment screw and set the idle to where it should be, which I believe should be 600-700 rpm lower.

 

What can cause a high idle? And what are the disadvantages? Premature belt wear? Premature engine wear?

 

i just got a 91 four door and my ls was idleing high (1.5k) too. it turned out to be that the throttle cable wasnt releasing all the way. when i would put my foot under the peddle and pushed up it would go back down to around 700. i dont know try it, it worked for me.

 

Sticky throttlebodies/cables/etc., out of whack idle air adjustment screws, failing intake air temperature sensors, piston ring wear, failing headgasket wear, overly rich fuel setting, overly retarded or advanced timing, etc. are all causes of as well as symptoms worsened by high idle engine speed.