As the title says my truck is down on power only when under a load, 3/4 throttle or wide open throttle. I just replaced the cam sensor, ipr valve and the icp sensor checks out good, fuel filter is brand new, i use 15w40 motorcraft oil. Truck idles fine,starts up great, maintains highway speed fine. I dont think it would be the hpop because thats mechanical and would probably cause running issues all the time. My fuel pump is very noisy when I turn the key to let the glows warm up. Could the pump be weak and not able to keep up under a heavy load demand?Needless to say im out of ideas and dont want to replace parts that arent bad and expensive, starting to ? the reliability of my 7.3 so help is appreciated greatly. Truck has 161,000 miles also and I did notice my hpop has a remanufactured sticker on it so it dosent have as many miles as the truck does.