My dad has a '90 K1500 with a 350 and a 5 speed. For a while now, it's been idling at a higher rpm than it definitely should. I'm sure it's some sensor that screwing it up, but which one would it be. thanks.

It sounds like a throttle position sensor to me. I am not to familar with that model year though. I am sure someone here has some xp with it though.. Sorry, could not be more helpfull..http://www.dieselplace.com/forum/smileys/Ermm.gif Edited by: Chevyfreek

it wouldn't have a TPS since it is trhottle body injection.

Hi DJ, Yes, your TBI engine has a TPS and no it's probably not the problem. The classic pattern failure is the gasket between the throttle body housing and the intake manifold shrinks from heat/age resulting in a huge vacuum leak. Easy fix, 20 minutes.

Hi DJ, Yes, your TBI engine has a TPS and no it's probably not the problem. The classic pattern failure is the gasket between the throttle body housing and the intake manifold shrinks from heat/age resulting in a huge vacuum leak. Easy fix, 20 minutes.

Mine did a few years ago on my 89.