I need some help. I have a 2005 F150 with the 5.4L. About a month ago I took my truck to an automotive repair shop because my truck would not go. I told the guy if i was at a stop and went to take off the truck would jump up to 4,000 RPM's before it would really pick up speed. I also told him that If i was cruising and going up a hill would have to floor it to maintain speed going up a hill. So I left the truck with him. After a whole month of him trying to fix the issue of what he says "engine wont maintain power" i have my truck back. The guy said that he even took my truck to two big Ford mechanics and they put it on all of their machines and still couldn't figure out the issue.

Bellow are his comments and the parts he changed out on the truck:
Comments: " REPLACED CAM PHASERS AND SOLENOIDS. T-UP DONE RECENTLY CHECKED BACK PRESSURE ON BOTH SIDES OK. REPLACED MAF, REFLASH ECM. CUT CAT LOOSE STILL NO CHANGE IN PERFORMANCE

Parts: CAM PHASER
CAM SOLENOID ACTUATOR
LEFT V/C GASKET
RIGHT V/C GASKET
MAF

More Info:
After picking my truck up I took it to another mechanic and asked him to check it out. his initial response with out looking was transmission torque converter. we got in the truck and he told me put the truck in gear and while holding the break rev the engine up to 2000 RPM's and wen we did that the engine stalled out and would not even bark the tires. we got out of the truck and he said I don't think its your transmission something is wrong with your engine but the things i would know to fix have already been done to it.

With all that being said my truck is still not fixed and im not upset with either of the mechanic's espically the first. my family has used the first mechanic for a long time and will continue to do so. they did everything that they knew to do.

P.S. I have minimal knowledge on this stuff so all I can do is tell you what I know. I hope the information helps.