Hello and a question!
I have to get right to the point 'cause I'm so flustered...I'm pullin' my hair out.
I have a 1999 Ford F150 6 cyl. that recently had a new fuel pump and filter replaced. Truck worked fine for about 20 miles then started to "buck" and cut out like it wasn't getting any fuel. Repair guys replace fuel pump again...and again the same symptoms only now it started about 5 minutes after driving.
Repair guys replace alternator saying voltage is swinging from 9 to 14 volts. When it drops to 9 volts pump would shut off then come on. OK...truck worked fine until about 20 minutes later starts bucking again and acting like the fuel is getting cut off. It doesn't really follow a pattern. It could do it in the first minute of driving or 15 to 20 minutes. Supposedly these repair guys have checked the fuel relay, etc. I kind of suspect intermittent open in a wire, but I'm not sure. Anyway six hundred plus dollars later it still doesn't run right. Please, any suggestions would be appreciated. Thanks!

May I suggest reading this:
https://www.ford-trucks.com/forums/s...d.php?t=300691


