Truck Repair: 2001 ford f150 4x4 5.4l, throttle position sensor, manifold vacuum

Question
truck runs great when cold - bucks and farts when hot - no power when hot - installed new spark plugs, new egr valve, new differential pressure egr control module, new fuel filter, i have access to robysis engine analyzer - no faults come up. worse when pulling trailer.  help pleze.

Answer
Hello Jay,
First of all, the sensor readings are mostly not used during warmup. The ecm uses default settings.
After warmup, the ecm reads throttle position, manifold vacuum, O2 sensors, temp sensors, and selected gear to decide how much fuel to inject, and where to set the timing.
I would connect a fuel pressure tester to see what pressure is being maintained first.
Then connect the scan tool and read some actual readings.
Throttle position sensor or oxygen sensor may be the cause. The analyzer should be able to tell if and how well they are working.

Van