start problem

[philly215]

hello everyone. this is my situation 2002 4.7l v8 w/157,000 mi. It all started with the occasional shutting off while driving and in the process of trying to figure this out it now starts and idles extremely high as if the gas pedal is pressed to the floor it then shuts off after about 3sec. it will start back up with the same results. Changed tps sensor, cam and crank sensor IAC . Can anyone tell me what other checks to perform as it will not stay running long enough to check much or is there a way.

 

[MyOhFive]

No codes?

Possibly a vacuum leak..?

 

[Redtruck-VA]

This sounds like the PCM is not seeing the Crank sensor signal and cutting the ASD relay down like it is designed to do. Check wiring and electrical connections. Check around the ASD relay for corrosion, broken wires.