i have an 88 f150 5.0 new high and low pressure fuel pump it doesnt like to start it cranks and cranks then finally starts it runs great after it starts i think im loseing fuel pressure when the motor

Fuel pressure regulator? Fuel Filter? Leaking injector? You all ready hit the 2 most common. It's possible that you have a fuel injector that's leaking down or not sealing well and not know it. The 5.0L EEC-IV injection system on that truck is non-sequential. In other words, instead of firing the individual injectors as needed, it fires 2 on each bank simultaneously (4 then 4). So if one injector messes up, it will be difficult to tell. Ypu would need some way of isolating and pressurizing the fuel rail to watch a pressure drop. A trick you can try: After a cold soak, cycle the key on for 3 seconds then off. do it a couple of times and then try to start it. The fuel pump(s) will run for 3 seconds without a signal that the engine is running. This trick works great to prime one that has run out of gas too!

My first thought was a plugged fuel filter. I had the same type of thing happen to my Plymouth Colt, basically a Mitsubishi built car. Just before I was going to get rid of it, this happened. I could crank on that damn thing for 10 minutes straight, no lie, and then it would start and run just fine. It was a bear to figure it out. Then I changed the fuel filter, and it stopped with the hard starts.