The above truck is in the shop now. The complaint is an intermittent lose of power while pulling a car trailer. If the customer pulls over, shuts the truck off, and restarts after 30 secs the problem goes away. The only code that I had was a P0093 ( Fuel System Large Leak Detected). I road tested the truck and was not able to get it to act up. With the Tech 2 when I comand the fuel rail pressure I will not go over 16,000 PSI when the desired is 23,000 PSI. When driven down the road the actual and desired are normal. What could cause this?