1995 ford f-150 straight 6 cylinder dies after about 5 minutes. will crank immediately but will not accelerate.

 

Check the fuel pressure.

 

My mechanic said fuel pressure about 40.

 

What else did he say and what are the codes and all other relevant information about the truck if you want any meaningful help.

 

My truck is a 1995 Ford f-150 straight 6 cylinder. It does not show any codes. Using paper clip method, it still does not show anything wrong. He put a new box of some kind on the fender well it did make it run better. Also put new pick up in distributor--made no change. Has tried several used parts off same model truck with no change in problem, including a computer, map sensor, coolant temp. Truck cranks up and runs fine for about 5 minutes--can mash accelerator wide open, idles great, etc. But after about 5 minutes it starts losing fire on 1 cylinder, then two cylinders, then 3 and dies. will crank back up immediately and idle fine all day, but the minute you depress the gas pedal, it dies. will crank back up immediately but will not accelerate..

 

I'd be first looking at the throttle position sensor. If that doesn't get it running right next would be the Ignition Control Module. Since you have a donor with apparently good parts, this shouldn't be an issue with throwing parts at it. I wouldn't rule out issues with the wiring.

 

He has checked the ignition control module and throttle position sensors---I can't remember all of the things he has done, but he said he has checked for relays (I ordered a repair manual for my truck and it does not show any relays--at least not any he hasn't checked), and tried everything he knows and nothing solves the problem. He has checked the wiring, including the yellow wire in the harness; fuel injectors are fine. Since the donor truck is running fine, we are assuming all of the used parts are ok. Seems to him like something may be heating up and not working---not sure. Also, do not understand why he can accelerate before it dies but after it dies and cranks back up, it goes dead when you depress the gas pedal. Is not flooding. Also, he disconnected the exhaust system and it does the same thing---thought it could be building up exhaust fumes. Does not have a vacuum leak.

 

Check the cats for back pressure.

 

He disconnected the exhaust above the catalytic converter, so there was no back pressure. It did not change anything. He has checked the wiring harness, tried 2 different coils, MAP sensor, Temp. sensor, ECM, 2 ignition modules, TP sensor and the fuel filter is clean. It will crank and run fine for about 5 minutes and then start skipping on one cylinder, then two cylinders, then three cylinders and then go dead. It will immediately crank back up and will idle fine all day But if you depress the accelerator after it dies and cranks back up it will go dead. You can pull it down into drive when it cranks back up and it will pull itself around the parking lot as long as you do not depress the accelerator. If you do, it will go dead.