Okay guys I got a 1985 f250 I just swapped out the original 6.9 for a lower miles 7.3idi when I first installed the 7.3 I threw in a set of new injectors and decided to rerun my 6.9 pump cause it was rebuilt about a year ago (25,000 miles ago) I sent out one of my extra injection pumps to have it rebuilt and tuned for the 7.3 I installed the new injection pump (without removing the top cover) and I had a hard time getting it to bleed the fuel pressure after many attempts trying to get it to bleed out I tried to tow start it with my other f250 and it still wouldn't get any fuel pressure so I pulled the new rebuilt pump and swapped on my 1 year old 6.9 injection pump and it fired right up but power felt a little weaker then it did before but a few times under hard acceleration I would feel the power come back again for a few seconds and then go back to running weak again so I tore it down so I sent the freshly rebuilt pump back to the shop that rebuilt it to have some testing done few days later the shop called me and said it was fine and they were sending it back so a few weeks later I finally got around to installing the new injection pump and I this time I got it to bleed out correctly and got it to run on the new pump that was rebuilt for my 7.3idi but it still seems weak on power basically when I first did the motor swap with my original 6.9idi injection pump mounted on the 7.3 it was pretty quick for a non turbocharged diesel then after the pump injection problem it hasn't ran the same since I don't have a deisel timing light so I know that needs to be set I plan to order a timing kit soon so I can set that I have 6 of these old 6.9-7.3idi trucks and this one has all the newest stuff new pump injectors new lift pump and is weaker then my 84 f350 with a jb welded cracked block on the block heater with 400k miles and lots of blow by original injectors and a injection pump that was replaced years ago and this truck has lots of injector knock so I know something is up with my 85 f250 with the 7.3 I know the timing needs to be set with a light and a pickup on the injector line but my main question is how likely could it be that the timing slipped under the injection pump housing iv replace quite a few 6.9-7.3 injection pumps this would be the first that I had to tear down the front cover to reset the timing gear the best way for me to describe the power loss is my truck used to pull trailers well I have 4" lift and 35s and a steel flatbed 4speed trans and I could run 65mph flat ground or up hill with a trailer with the ac going after the power loss started it won't go over 50 with a trailer or a boat behind it this is my daily driver so I would really like to get this power issue resolved it fires right up and doesn't smoke at all not even at wide open throttle I just took it on a 600mile trip to the beach and it got 17mpg running the way it is right now but I really feel the power is just not there you can really feel a trailer or if I load up two atvs in the back of the truck you can really notice if anyones got some ideas things to try let me know I wanna try to keep this truck away from the deisel shop if possible