this problem is intermitant. i am driving along at 45 mph and the 4.6 dies. sometimes it will come back on and sometimes it won't. it isn't tossing out a code. it did it this last weekend trying to park at the denny's (15 mph at the most) sometime it will die while sitting at the light. no miss or clue it is going to die. the truck is a 97 f-150, 4.6 auto

 

so its just shutting off immediately?? no sputtering,hesitattion?? weird noises??. sounds like an electrical problem. check all your main grounds. my old dakota did the same thing. turned out one of the main grounds was corroded.

 

It never "tosses out" codes - you have to pull them with a scantool. What's your fuel pressure?

 

we scanned it for codes and nothing showed up. fuel pressure is good. it just shuts off. no warning. no bumps in the road at all.

 

You need to do the diagnosis WHILE it won't crank. Fuel pressure, codes (or at least observe the MIL), spark...

 

that's just it. it fires right back up. there is no sitting there cranking it. it turns over the first time.

 

Sounds like a PATS problem - does that truck have it?

 

what's PATS?

 

Passive anti-theft system. Mines a 97 and doesn't have it

 

i don't have the factory security system

 

my vote still goes to a bad ground or something like that.

 

i am going to check all that out this weekend.