Turns over but sometimes doesn't crank and stalls
 

I have a 2001 f-150 4.6 v8 it turns over but doesn't crank sometimes . And when it does crank after about 45 min of driving I will lose all acceleration and have to turn it off and start it back up to get acceleration again . It also stalls if I'm idling to long. Any ideas what might be the problem?

I barely understand the question. It turns over but doesn't crank sometimes?

Check for codes?
When was your last tune up?
How many miles on the truck?

It's acting like it's out of fuel but theirs fuel in it , and when it eventually cranks it I lose acceleration power after about 30-45 min

The motor turns but it doesn't start sometimes

"Turn over" and "crank" are the same thing. You mean it turns over/cranks but sometimes doesn't fire/start?

When was the last time you changed the fuel filter? Have you tested the fuel pressure with a gauge? Do you hear the fuel pump run for a couple seconds when you turn the key on?

I hear the fuel pump turn on and haven't changed the fuel filter

You're making it difficult for us to help you as you are not answering all of our questions. Did you check for codes? When was your last tune up? Have you tested the fuel pressure with a gauge? How many miles are on the truck?

You guys must be on his ignore list.

It's the only thing that makes sense.

Some people are very low on the Totem Pole so have patience and help him along.
Good luck.

That's what post #5 was for... Still nothin.