Idles high after going from park to gear and back.

[ChevyTech]

Originally Posted by MadRatt

Also thought this was weird but why when I rev the rpms up why does the iac counts go up? I thought the iac was only for idle. The higher I rev the engine the more open the iac goes. Shouldn't it be closing the more the butterflies open? I'm going to actually drive it tomorrow and see if it's also doing it while driving.

That is designed in. It is like a dash-pot used on some carburetors. It is to slow the deceleration of RPMs to prevent backfiring in the exhaust.

Does your truck have a tilt column that has gotten loose?