Hi there..

Short story. The engine is a 87 Lg4 engine that I converted to TPI 2 years ago. I used a TPI set from a 89 camaro so I have deleted the cold start injector and the EGR. I am also familiar with chip burning so I have burned my own chip.

The car is acting okay when driving but I am not satisfied with the idle and the unstable idle after driving for a while.
I have set the idle at 700RPM in drive, cause I have a cam with some higher lift so the engine stalls at 4-500rpm. After I drive for a while and stop the car and put the transmission in park or neutral the RPM jumps to 1300-1500RPM. It feels like the car is being "choked" somehow.

Anyway. When I am adjusting the idle RPM with the IAC plunger fully extended it sounds like the engine operates nicer.
Have anyone of you had some troubles with the IAC valve??

 

Sounds like the IAC or a vac leak to me.

 

I don't think it's a vacuum leak but I will check with a vacuum gauge today. I am more focused on the IAC because when I do the idle RPM adjustment with the IAC plunger fully extended the engine sounds happier with only the air that goes through the throttle body.