I have a 97 4.6l with 147,000 mi. A few days ago the truck started stalling out when I would come to a stop. I figured it was the IAC. Just to confirm my thoughts I took it to the dealership. They confirmed that it was the IAC sticking intermittently. So I cleaned it, the problem did not get any better. I then bought a new IAC from AutoZone. The problem got worse with the new part. I went to the dealer to inform the service manager of my findings. He stated that it was a defective part, and that I should only by ford parts. Since the part was twice as much at ford I decided aginst buying it when I figured i allready tried it. I have since tried another IAC from another parts store still no better. I have new egr,pcv,plugs,wires. The check engine light has not come on either. The vehicle idles fine in neutral,and the problem is worse when the veh is warm. I have run out of ideas any advised would be greatly appreciated.

 

whens last time u had ur transmission serviced. does it have a built in tranny cooler? could be the TC is locking in at return idle that will cause it to stall out. but id check for vacume leak somewhere and then check the idle air control valve.. ived for 2-3 of em around here that work if ud like to try em

 

well honestly in the 4 years i have had the vehicle i have not had the transmission serviced. perhaps that is part of my problem. would that make it downshift hard into first gear when i am breaking. it has been doing that since this problem started

 

I have the same truck. It now has the same problems. Did you fix the stalling issue? I also replaced my IAC valve.

 

Have you cleaned the idle air ports on the elbow behind the throttle body? They can become clogged with carbon and cause idle problems.