I replaced the blown head gasket due to overheating, along with other incidental gaskets and thermostat. The issue I'm having now is the engines idles around 1100rpm with the idle adjustment screw completely closed! Touching the throttle jumps the rpms to 2200. Once the engine warms up and the thermostat opens, the speed drops to around 1900-2000rpm. Blipping the throttle usually drops the idle back down to 1100rpm.

Truck is an '85 Pickup SR5 w/ 22re, 5 spd, no A/C.

I did clean the throttlebody while still on the plenum when doing the original engine work. Today I removed the throttlebody, blew out the vacuum passageways, and checked the TPS with a multimeter to rule it out as the culprit. Everything tested out perfectly to specs in the FSM.

The throttle isn't sticking, either at the pedal or at the linkage.

I'm suspicious that this may be caused by the Idle Air Control Valve being partially blocked open, but I've also read that the IACV would only be suspicious if the idle were low and not high.

The exhaust is also making some light puffing sounds that aren't normal compared to pre-HG failure. Might this be due to timing? I am planning on checking and adjusting it after I get the idle issue resolved.

Any thoughts? I've searched and read a ton but still no closer to figuring this out. Please help!

 

Vacuum leak or timing too far advanced. Or both.

 

Okay, so apparently I didn't plug in the IAC electrical connector. I can't remember there being one on my '88 (previous to this truck) but I know there were some changes to this system after '85.

Problem is better but not resolved. Idle now settles at 950 with the idle set screw closed. Touching the throttle still results in a high idle although lower than before. Maybe 1600 or so.