96 Z71 High Idle Problem

[JAP5583]

I have a 96 Z71 and it has a high idle problem. I idles at 1400 rpms and when you push in the clutch when moving the RMPS will go up to about 2000 rpms and hold. I sprayed the engine with carb cleaner to see if there was a vacuum leak and didn't find anything. I cleaned the throttle body and replaced the IAC valve. I replaced the TB gasket and the upper intake manifold gasket and it hasn't done anything. I had it hooked up to a dianostic machine and it didn't tell me anything but that the O2 sensors and and the MAF sensor are working fine. I am gonna get the timing checked and change the TPS sensor and see if that does anthing. Has anyone had this problem or have any ideas of what could be causing the problem?

[toivo]

when you repaced the iac did you recalibrate it? it has a process to go thru to reset it.and also check the main idle speed without the iac in the picture.

[Thunderbolt]

I agree with setting the IAC and as far as timing, You need a scanner to set it. It should be set at 0 plus or minus 2, But can only be done on the vortec with a scanner hooked up.