[Concrete chic]

93 Sonoma 2.8 is idling around 3500 rpm's. I took the IAC out replaced the gasket and torqued back in about 10-13 lbs. Now on startup it is a constant high idle. I've pulled the negative then the connector tried to trace down any vacuum leaks but idle is to high to run. Map sensor has been checked iac has been replaced and put original back on. This idle problem started after I pulled the iac

 

[oldeerslayer]

Why did you pull the IAC? Sounds like you got something incorrect on the re-install if it wasn't doing it before.
Would have to see it to be able to tell. Did you do anything to the IAC while it was off? Like put power to it to watch it move? Did you also "fix" the TPS?

 

[Rebel n Dirt]

I was a tech for GM back in the late 90's. I remember some rigs needing to have the IAC put into a relearn/calibration mode before installing them. Kinda like the CKS needs. This would let the computer know where the IAC was in it's travel to get the idle speed right. Removing the IAC though will not get the throttle up to 3500 RPMs, that sounds like something kicking the throttle valves open too much, where the IAC is not even being used. As a GM tech I had access to a Tech2 for this job and it only took a few minutes to finish, I do not know if there is a backyard way around this as I try my best to avoid ALDL vehicles(95 and older) all together.

I would check first to make sure there is nothing getting in the way of the throttle valve, or throttle cable. Check for vacuum leaks and also make sure the MAP is plugged back in to both vacuum and electrical.