Ford Repair: ford 5.0 stumbling, air controler, time bob

Question
I have a 94 full size Bronco with a 5.0 with 85k on the motor. It runs out very strong, just recently when I am stopped at a light with the truck in drive and holding the brake on the engine stumbles, idles down and some times stalls. Putting in back park it starts back up with no problem. It does not do this all the time, only after running for 30 minutes or more. Can you help?

Thank You for your time

Bob

Answer
Bob,

You should try cleaning the idle air controler first or IAC. It is mounted on the side of the throttle body with 2 8mm bolts holding it on.  Remove it and soak it inside the two passages with cleaner. I suggest using foamy engine bright as it seems to work great on cleaning the carbon build up out of these valves.  Let it soak a while and then clean it again. Re-install it, disconnect the battery and wait a minute or so to clear the ECM memory. Next hook the battery back up and start the vehicle. It may stall a few times since it has to re-learn the idle stratagy. It helps to idle it in gear with A/C on and off a few minutes then should be fine.