Ok, about 2 weeks ago i was on my way home and it started to jump and buck and sputter like it was out of fuel. I know i had like half a tank and things were ok. I swapped to my rear tank and figured i had enough gas in there to get me home. I got home and all was well. My beliefe was i need to replace my front fuel pump and that would happen when i could do it.

I noticed over the last week i had some misses and on the way home from work it sputtered a few times like it was starved of fuel. Im thinking. Damn... I made it home. I did a tune up on it which included plugs and wires and cap and rotor and Air induction cleaning and air filter and fuel filter and raidator flush and changed the oil in the motor and trans and front and rear diffs as well as the transfer case.

I was thinking a nice tune up would do the trick..... WRONG!... once the truck was warmed it it sputters and dies. I got a fuel pressure gauge on the fuel rail and when running it reads between 36 and 40 PSI. Until the thing starts to sputter and then fuel pressure drops to zero. I replaced the external fuel pump that sits inside the frame and still does the same thing. I unplug the fuel regulators vacume hose and it still dies.


So here is what I'm thinking and maybe someone can help me on figuring this out.
It craps out when warm. This tells me it is probably not the fuel pumps in the tanks cause when it is warm it dies on both tanks after running long enough to warm up. I also notice in the bleed line on my fuel pressure gauge there is lots of air bubbles.


Thanks in advance for any help.
Kalira
Hopefully still a proud Ford owner.

 

I had a simular yrear and put a ton of parts in the fuel system and it ended up being the fuel pump relay. I would start there

 

Well you need to find out why it drops to zero when worm? Just cuz it's a new full pump don't mean it's working. I would start there, Run a bypass line and let that thing run by its self until it gets hot. You should have the same psi all the time.......

 

when you re recording good fuel pressure, try pinching off the return line and watch the fuel pressure-if it drops way down bad fuel pump. aslo perform the fuel pressure regulator test