I have a 2003 with the 5.4 L and at times it acts like it does not have power. New plugs coil packs, EGR Sensor and Vac lines in last 20,000 miles, engine has 200,000 miles total. I was pulling a 5x8 uhaul trailer and notices that i had no pulling power. Any thoughts? I have pulled many trailers and its pulled fine.

Please help

 

Low fuel pressure, clogged fuel filter, clogged cats...just to name a few possibilities.

 

Are you seeing the loss of power when the engine gets to a certain RPM?
Our 2003 5.4l runs smooth until it gets to 2800 RPM, then no more power.