Slow pickup
My 97 f150 xlt 4.6 just bought try to tow 15" utillity trailer empty was struggling to get up to highway speed and also hearing some grinding while accelerating had to slow down below speed limit
or is it a sled deck and you've got a headache rack on it acting as a wind absorber?
as for the grinding.... i'd pop the plate on your rear diff if you don't have lockers.

