Idle surge, low power when towing.
I could use some thoughts before I take the truck in to be looked at.
For a while now, the truck (04 F250 6.0L PSD) has been surging when idling. Sometimes when it happen it could almost jump into the car in front if the brake pedal isn't pressed hard.
It usually happens when warm and more frequently when the fuel gets down to about 1/4 tank. The filters have been changed and the problem 'almost' goes away with diesel kleen in the tank, but not quite. It happens when driving around town but never when getting off of the highway or after towing.
Possibly related, I was towing my 10,000 lb 5th wheel this weekend and when coming home on Monday, it felt at times like the truck was struggling. Normally the truck just flies but on Monday, it seemed to have trouble keeping 65MPH. It also had a lot of turbo whine during that time where you usually never hear it. The turbo seemed to wind up and down repeatedly.