Lets start over

First how do you know its extended 100%

Second Im guessing you mean a 3.9 not a 3.7

#3 have you rebuilt it or cleaned out the throttle body these usually need a good cleaning?

#4 the IAC units usually don't go bad my guess the TPS is bad they go bad all the time or the throttle body is gummed up.

My TPS has needed replaced many times for Idle problems oem or quality is needed for a TPS.

 

As Heyyou said do the full reset .

Yes off brands can be a factor .

If you can ,rent scan tool an do a live data test an see what the different sensors including the map an tps is reading..12 is good on tps in idle.

 

Hey guys. Thanks for all the good advise. Unfortunately I ran out of time and had to work out of town. My girl needed the truck so I put it in the shop. They said they scanned the system, test-reset and relearn IAC System, cleaned the housing and replaced the air filter.
So far so good.Sounds like you guys where right on about the relearn. I will know for next time.
Thanks again!