My cousin has a 2002 f150 xlt triton 4.6 and it has a stalling problem. At first it would randomly stall while driving and then he would have to wait a few minutes before it would restart. It would crank but not start. It progressed to the point where it will now only run for 10 minutes and then stalls. Would not restart for a few hours unless you shoot starter fluid in then it will run for a few more minutes but then stall again. You can restart it that way 2 or 3 times then have to wait for a while before it will restart again. He has replaced many parts including computer, coils, iac, egr, fuel pump, can sensor, crank sensor etc ... It seems to be fuel related as you can restart it if using sarter fluid and then spray gas into throttle body once its barely running. When it dies it justs shuts right off most times sometimes misses. There is 40 psi on the fuel rail when dies. Anyone have any ideas or see anything similar?

 

Your indications are pretty safe it's a fuel issue.
Why was all that money spent on unrelated parts instead of tracking down the lack of fuel cause, then the repair for that?
The only way the motor gets fuel is through the injectors at proper pressure.
Was the injectors tested for pulsing at cranking when the problem is there?
Was power to the injectors tested for?
If all that is needed to get the motor to run is gas introduced through the throttle body it's a pretty clear cut case everything else is ok..
Are there any codes present?
You have to get a lead before replacing any parts.
Good luck.

 

Check the injector pulse while running and monitor during a stall or like bluegrass said, during a no start.

Wasnt there an issue with the fuel pump relay (connection, corrosion, heat soaked or something) that had symptoms like this? Although he says there is 40 psi even during the stall.

 

Some things were not needed. I am trying to help him now so he does not replace more unneeded items. Anyway there is voltage at the injectors. I also can hear the injectors with a stethoscope. He had someone read the codes and there was a P0320. Some places state it is for the crankshaft sensor and found one mentioning ignition coils , wires , plugs (which were replaced, noticed AC plugs). He told me the problem has been going on for months and that when the temp outside was below 20f there were no problems, not sure if that was a coincidence or not because the problem back then was not as severe as now. Any ideas as to the code? Thank you

 

If you are going to shotgun any more parts at it, I'd change the crankshaft position sensor.

 

Crankshaft sensor was changed and I dont shotgun parts ... thanks

 

Check for codes again.

 

That code is after he changed it ... thanks

 

The crankshaft position sensor was changed, the codes were cleared and the p0320 came back?

 

Yes