irlndu2

Greetings all,
Just a heads up, i am not a mechanic nor havent i owned my truck (v8 5.4 3v) for that long. i am familiar with the basics and handy with research. Ill jump right into the problem

truck will not stay running though it turns over and smells a bit gassy after a few attempts. It does start 80% of the time but dies off at the 1-2 seconds mark. The problem occured while i was stopped at a light and the truck wouldnt move, due to it being off. i had just driven it 160 miles 2 days prior no issue. I had no inclination to any issues prior to that point. With ODB scanner hooked up KOMO pressure is about 75psi (i believe this to be way too high)
Things i have done include:

ODB scanner shows no codes. (though i do have a check gauges light) on the right side if i do not try to restart truck
changed out the FPDM
changed O ring gasket to fuel rail pressure sensor
changed TPS
thoroughly cleaned throttle body, (nearly spotless)
changed out air intake for cold air intake
changed all plugs and coils
changed out R01 relay

I do have the standard chain/guide noise at startup when it was running but only lasted the typical 4 or 5 seconds till oil pressure up.
I lack to the do the following which i have the parts for yet am doubtful it will matter much,
changed fuel filter
change crankshaft position sensor
double check the fuses for a bad jump

Clearly i would appreciate any kind of tips or advice anyone can offer and if i left any needed information out feel free to let me know, thanks again!

F150Torqued

Slow down and take a deep breath. Put your parts cannon away.

Raw Fuel Smell. Recent Plug Job. *Take the time to recheck Spark Plug Torque (with torque wrench, no guessing at 25 ft-lb). Make sure plugs are FREE of greasy finger prints and that you have NEW boots, and a little dab of dielectric grease on the plug end of the Boots.

On your Fuel Rail Pressure. What do you mean KOMO? is that KOEO - Key on Engine Off? The fuel rail pressure sensor is VACUUM referenced by a vacuum line into the bottom of he intake manifold. You would be much better off reading OBDII Fuel Rail Pressure KOER (engine running). You should have around 38 to 40 lbs - "relative to intake vacuum" if the Fuel Rail Pressure sensor is working correctly and it's little vacuum reference vacuum line is in tact. You can also disconnect it's vacuum line - connect a piece of vacuum hose on it and "SUCK" on it, and observe fuel rail pressure reflect change per your suction to verify it is actually working.

irlndu2

Thanks for the input, i will certainly give that a go. my KOMO was key on motor off so yes the koeo. My truck wont actually stay running for any amount of time so i only have the KOEO readings. Appreciate the additional advice on spot to look at, thanks !