My uncle told me to always check the lift pump first, and man, was he right about that 6.7 Powerstroke

I was working on this 2015 F-250 last week, the thing had a rough idle and would just die at stoplights. Spent hours scanning it, checking injectors, even pulled the fuel filter housing. My uncle, who's been turning wrenches since the 80s, called and said 'Brian, stop overthinking it. Put a gauge on the fuel rail and check that lift pump pressure before you do anything else.' I mean, I figured the computer would throw a code if it was that simple, right? Hooked up the gauge and it was reading 45 psi at idle, but the second you gave it throttle, it dropped to like 10. Sure enough, swapped out the in-tank pump assembly and it runs like a top now. I wasted a whole afternoon because I didn't listen to the old-school advice first. Anyone else have a 'simple check' they always skip that ends up biting them?

3 comments

3 Comments

sagecooper1mo ago

Sometimes the computer just misses the obvious stuff, you know?

leo_black761mo ago

Nah, I gotta disagree with @sagecooper on that one. The computer's just reading what the sensors tell it, and sometimes the sensor data looks fine even when the part is failing. That pressure drop under load is a classic mechanical failure the computer can't always catch.

elliotm571mo ago

Reminds me of my old truck's transmission. The computer said everything was fine, but it would shudder going up hills. Turned out a worn clutch pack was slipping just enough to feel wrong but not enough to trip a code. Felt like the truck was lying to me.