Injector pump or not????

[Kyoming]

I have an 02 Dmax with 252,000 miles. It started losing power a few months ago and turning on the SES light. Sometimes it would go into limp mode until I turned the light off. I have taken it to the dealer a couple of times and they have "thrown parts" at it but it still acts the same. Only difference is that my bank account is alot lighter. Some people say its the inj. pump, others say no its not. Everyone that hooks it up to a machine says that the fuel pressure is half what it should be. Is it really the pump??? It starts great. Doesnt lope . But it runs weak. Always downshifting to pull a hill. Fuel mileage has dropped to about 14, it always got 19-22 mpg.
In the back of my mind I keep wondering if the fuel sock is partially clogged?
Some people even say "well it could be the tranny" that throws the code and causes limp mode because the clutches are slipping a little. IT DOESNT HAVE ENOUGH POWER TO SLIP THEM! Its not burning oil but it does smoke more than it did before. Its not chipped (anymore). Any thoughts????

[ob_1jr]

Well, if you haven't changed your fuel filter in a while, I would start there. Did they change the FPRV? (fuel pressure regulator) I would think that if the injector pump was going out, you would be seeing other problems. What codes do you get when you get your SES light?

[Kyoming]

I change the filter religiously and I just had a fuel pressure regulator put on it two weeks ago by the dealer. ($1400,00).
The SES light comes on but doesnt always have a code. At least not on my code reader. When it does throw a code its an "overboost" code. I also replaced the pressure sensor by the turbo a couple of weeks ago.

[ob_1jr]

Well, that overboost code will cause your truck to "limp." I know PPE has a code elimitator for that. Check it out at pacificp.com. I would go that route first since it is a whole lot cheaper than an injector pump.