I just got this truck. 1999 F250 4X4 with the 5.4L. It will start great when its cold but after you get it hot and it sits for a bit it will not start (will crank) again till it cools off.

Its has new MAF coil packs and plugs, airfilter tranny fluch and oil change.

Please help

 

This reminds me of a fuel pump issue I saw on a 5.0L once. From observation, it was the fuel pump had reached the end of its useful life. When it (pump) was cold, it would run fine, and start without a problem. Then after it had warmed up, it simply could not raise the fuel pressure sufficiently to feed enough gas. Observe the sound of the pump when you turn the key on while cold. Once you're back from your grocery run, shut it off, then turn key on and listen to the pump again. Might work better if you lie underneath the fuel tank and have someone turn key on for you.

Sent from Nexus 4. IB AutoGroup

 

I agree with 73fan. sounds like the pump is getting weak when it's hot