I can't help with this problem as I am trying to sort a similar issue with my ute - 1999 TD42 with aftermarket top mount intercooler, reconditioned motor fitted about 20,000km ago, injector pump overhauled at the same time. My symptoms started with an occasional brief 'flat spot' going through 2,800rpm. When it became consistent I opened the drain on fuel filter to check for dirt/water and found nothing, cranked it up after doing that check and it wouldn't pull above about 2,400rpm. 50km later it wouldn't rev above 1,700rpm, If I slowly increase throttle it gets to 1,700 without a miss but if I apply more throttle the revs drop back to 1,400.

I've checked all the obvious - filter/tank vent/fuel lines. I eventually put a fuel container on roof and gravity fed direct to injector pump and still got the same symptom. I'm guessing this points to a problem with injector pump and am hoping someone might have an answer. I've read about the gauze strainer but have no idea where to find it ! I undid the banjo fitting where feed line goes into injector pump but couldn't see anything in there.