1993 4.9 5 speed 4x4
I installed a new fuel pump the truck ran great about a week later it started sputtering and hesitating like it was running out of gas. So far ive changed plugs wires dist cap fuel filter fuel pressure regulator and 02 sensor. At first there were no cel coming on then it would come on and go off now when it comes on it stays on when its warmed up. It revs fine in neutral and have to pat the gas while cranking or itll almost stall. Starts sputtering and loosing power under acceleration and if i stomp the gas then ease back off to about 1/4 ways down itll pull on out and it gets worse and worse the longer it gets drove. No vaccum leaks. Also pulled the codes and it said fuel pressure regulator circuit failure but i put a new fpr on the truck. Ive been told to check the sock on the new pump but that wouldnt make the cel come on

 

EDIT: Did not see you had the codes pulled.

Check the connection and voltage in wiring harness to see if the sensor is getting power to it.

 

Consider the possibility of the new fuel pump failing. Suggest to check the pressure on the fuel rail - would like to see a stable 35-40 psi.

 

Not the first brand new fuel pump to fail (as wde 3477 said), especially if you only paid $100 or so. You need to get a gauge and check the pressure to be sure before you waste any more time or money. With a brand new pump, I'd expect 42 to 45 psi as soon as you turn the key to on.

 

I'm having the same issue, but I got code 327 - which I don't funny understand. I have not checked the fuel pressure yet, but that was a consideration.

 

Would the cel come on once the truck is warm if it was the fuel pump

 

So I checked the fuel pressure and that's all good at KOEO and running. I also get code 565 Canister Purge Solenoid -

Truck sputters and has no power so I am at quite the loss.