After towing/highway driving for 30-45 minutes, and downshifting to a lower gear, I'm getting hesitation/bucking for 3-4 seconds before the truck accelerates. The truck also does it without any load, after driving for a while.. It only occurs on downshift, when power is demanded. It doesn't do it around town, and you MUST drive at a constant speed for at least 30 minutes for it to start happening.. Once the truck hesitates.. it usually won't do it again for a few miles.. In other words.. if it hesitates.. and goes to the next gear.. If I immediately make it downshift again, it won't hesitate as badly, or sometimes not at all.
The truck is has a build date of 2/07, and it is a 4 door, 4x4 lariat with torqueshift auto. There are no trouble codes, and the truck has the 07S49 recall done.
Not sure what to do.. Ford won't do anything since they can't get it to reproduce the problem. I think it's something fuel related.. boost pressure falls off when the problem occurs.. Trans temps are fine, and I don't think it's the converter.
Any ideas? It sucks to pay 50K for a truck and not get any support from Ford..
Travis