New mystery
So now I have a weird mystery. The truck attempts to die while in gear when under any throttle, and while attempting to turn. It idles fine initially and can idle great until some form of load occurs when in gear. I checked the tps and it changes from 0 to wot.
Yes it does. Also has no pending cels,or anything to indicate why the motor wants to stall out. Literally it will drive ok for a minute or 2 after first start up and then require multiple restarts and moments between cranking.
What year and how many miles on it? What engine and drivetrain set up do you have? It sounds electrical. It cranks over okay but won't start, right?
2001 4.7l 4x4 qc with approx 206k The truck starts and idles fine, even revving it. It's not until the truck gets into a gear and it's not instantaneous that it keeps wanting to stall and succeeding. I just put the engine back together after finding a dropped seat on the number 7 cylinder. So it's got a new timing chains, oil pump, pickup and pan as well as anything that had a seal. I also just replaced, the trans filters and changed fluid. (6.5 qts). I'm able to get the truck usually to the first stop sign around the loop .3mi away before its interested in stalling. Then once it stalls, I can usually crank the truck back up, but if I give it any gas, or try to turn once rolling a bit after being in drive it just dies
I'm no 4.7L pro, but it sounds to me like the fuel pump is on its way out, and it's possible that the factory wiring harness plug may need to be replaced. New fuel pumps come with new pigtails. You can get a fuel pressure tester and see where it sits at, both at idle and in gear with someone holding the brake. This could also be a fuel filter issue, as it appears that the fuel filter is also the fuel pressure regulator at least according to Rock Auto. The pressure check at the rail should also show this, and I'd replace the filter/regulator before dropping the tank for a fuel pump replacement.
On the other hand, from what I hear about the 4.7L it's really, really touchy about needing the timing chains replaced exactly spot-on, but I have no direct experience with this or what symptoms it might present if it's just slightly off. I only mention it because you said it was just changed.
On the other hand, from what I hear about the 4.7L it's really, really touchy about needing the timing chains replaced exactly spot-on, but I have no direct experience with this or what symptoms it might present if it's just slightly off. I only mention it because you said it was just changed.
Fuel pump is brand new. It can idle for 10 minutes without an issue. This truck has an filter inside the tank.
Last edited by angrysmileyface; Feb 21, 2021 at 04:43 PM.













