Throttle actuator problems?
 

I have an '05 F250 w/ the 5.4. The last two mornings have been the coldest two mornings so far, and both mornings my truck has had issues. Yesterday morning it seemed to be idling low, the wrench light was on, and when I got to the stop sign at the end of my road I tried to accelerate and nothing happened. I turned the truck off then restarted it - no problems and no wrench light. This morning started the truck and a rough idle then sputter on acceleration. Turned the truck off then restarted it and runs fine but the check engine light is on. I brought the truck to a shop near my house (not a Ford Dealership), and paid for a diagnostic check and I was given an estimate for $1100.00 for "Throttle plate accuactor motor needs replaced," and the truck shouldn't be driven anywhere b/c I will get stranded. He would not give me a diagnostic printout and, but after some research I assume he is talking about the TAC motor. I have read other threads and have noticed similar problems in cold weather with the TPS, so I'm not absolutely sure that it is the TAC. I didn't get the truck repaired at his shop, and drove about 80 miles today without any problems in addition to about 80 yesterday.

I have three questions:

1. What is the likelyhood that this is really the TAC?
2. How difficult is replacing the TAC motor?
3. How urgent is this problem?


Thanks so much for any help.