Wont sart after long periods of driving/warmed up

[95ranger4x4]

I have a 1995 ranger 4x4 4.0 v6 automatic. For some reason whenever I drive for distance longer than just a few miles or for a period of time longer than about 20 min (well beyond the engine warm up period) i cant get my truck to start after turning it off. I have to sit there and let it cool down before it will start back up again. This usually takes about 30 min. I also noticed that if i rev the engine from idle, the rpms will drop down to around 500 and the engine will shutter until it goes back to normal rpm. It runs perfectly fine while driving until i turn it off. No drop in idle or shuttering. It also starts fine when cold. I have already changed the fuel filter, coil pack, sparkplug wires, and spark plugs. Im thinking of changing the fuel pump or fuel pressure regulator next. Ive also heard it could be a computer problem. Any suggestions?

 

[jonesda123]

let me know what you find out because my father in law has exact same problem with his truck and has done everything you mention except the fuel pump

 

[Jspafford]

I had something similar on my 2.9. Well, mine started idling higher than normal. Then it became hard to start once fully warmed and not allowed to cool.

Turned out to be the coolant temp sensor.

 

[97ranger4x4]

Well before you replace any more parts you can often test them to see if they are working properly.

An easy test for the Fuel Pressure Regulator (FPR) is to remove the vacume line off of the FPR. If you see any fuel come out of that line than you know the FPR needs to be replaced.