Engine/Transmission (1998.5 - 2002) Fuel Starved when accelerating, especially when towing.

[LPMorgan]

I installed an Air Dog pump and my fuel pressure gauge shows 12 PSI, but when tested it shows 16 PSI. The pressure drops minimally if at all when towing. However, the engine often acts like it is fuel starved. The fuel pump is good and filters were just changed. Air filter was changed. VP44 was changed last year. Injector coonects have been tightened properly and are not leaking (they had been).

The problem is worse when towing my 10,000 lb trailer uphill as even a mild acceleration can cause the issue, but rapid acceleration can cause the engine to act fuel starved even when not towing.

NOTE: Replacing fuel filter, air filter, and tightening injectors each decreased the problem, but did not eliminate it.

I get no codes when I hook up diagnostic tools.
Truck has over 200,000 miles.

With what I have done, what is the next step? Do I need to replace fuel injectors or is there something else?

Any suggestions appreciated.

 

[JR]

What kind of diagnostic scanner are you using?: Where is your fuel pressure gauge tapped? It sounds like there is a decrepency between two gauges, if your main gauge is electrical you need to verify pressure under heavy engine load with a mechanical gauge. Fuel pressure at idle only tells a small portion of the story.

If everything above checks oat it's time to start eliminating some electrical possibilities, having batteries load tested, checking all battery connections and grounds to ensure they are tight and corrosion free. Also could try an APPS reset while your at it.

Injectors are a possibility but if it were me I would try eliminating everything else first before condemning them. with your mileage it is a possibility they are worn but I have seen trucks go 400k on original injectors. My Former 2000 has close to 360k and still going strong on originals. If all else fails and you want to be sure you can pull them out and send them out to be pop tested.
Many times your engine oil is a good indication on worn injectors (but not always). If your making oil or the oil smells like it has fuel in it you likely have a bad injector (or more) and need to be very careful about driving the truck.

 

[BMelhuish]

Check the wastegate and wastegate actuator operation. However, you usually get an overboost code. If you have an overboost, the PCM will defuel the pump at higher RPMs and loads.

 

[MLee]

DO you have a Exhaust brake? if so, could it be activating at this point? just an idea.