2006 V10 in a motor home. less than 25000 miles but on a trip in July the truck went to idle, I really thought the transmission went out. After a couple of weeks the mechanic ( I was 300 miles from home) called to say the truck was fixed, he put in a new throttle body. Went to get the truck on a Sunday and started back and the truck went to idle less than 5 miles from the shop. Let it sit for a few minutes and started back up, went another 100 miles and it went to idle again. Another 100 miles and the same thing happened. Finally got it home and took it to my mechanic and he ran the codes, same code that the throttle body was stuck on high. He relearned the throttle body and I drove it on short trips, under 50 miles with no problem. Last Thursday we started on a trip of 268 miles, 100 mile into the trip it went to idle and I coasted to a stop and restarted. Made it the rest of the way to my destination. Sunday I started home and a 100 miles into the trip it went to idle, pulled over and restarted, 70 miles later it did the same thing. Restarted and made it home, anyone have an idea about what is wrong? My next step is going to be to replace the new throttle body in case the new one I purchased was defective but that seems a bit of a stretch

 

YOU need to run the DTC's or have someone you trust read them and share with you. There could be up to three DTC's related to those symptoms, two related to the throttle body being stuck open or closed and another citing the "forced idle" condition.

Also confirm the throttle body is new and not re-man'd---there will be obvious signs of this. If this "new" throttle body has been replaced is there any warranty?

I had this same condition on my 2005 E-350 w/5.4 engine, new Ford TB was under $300 and swapped DIY in under an hour in the driveway. This isn't all that common but very possible in models with the "fly-by-wire" or electronic TB's from 2005 until who knows when or 2013 which was EOL for the full bodied E-Series..

 

Codes are P2104 and P2111
2104 is TAC System-Forced Idel
2111 is Throttle Actuator Control system stuck open

 

That pretty much says all that needs be said! Have you bothered to confirm whether this "new" TB is indeed new OEM and does it have any sort of warranty? If this is a Ford factory part it will have a two year warranty period.

It's highly unlikely if a new part was indeed installed it too has failed so quickly after installation. Following this top-rated YouTube contributor: This might be helpful but honestly I have my doubts it will solve your issue.

Best of luck!