power problems....

so yeah, i have been having problems with my burb. it seems to be a complete dog when climbing hills. it happened one day when i woke up, and cant figure out whats causing it. i have great acceleration off the line, just no power as i get going fast, or try to climb grades.

its a 95 gmc 1500 4x4 burb. ive replaced a lot, the list is in an older post. i took it to the mechinc in my town that everyone recommended and they all said "if anyone can figure it out, its him" well, he had it for 2 days, and couldnt figure out whats wrong. he didnt really notice a problem, but did not drive it over a large grade. he checked for trouble codes, ran the diagnostics on it while driving, etc. he advanced my timing about 4 degrees, it helped a little, but its still not the way it was 2 months ago. any ideas???? im pissed and about to give up. it has 160k miles.

Losing power over a long grade and not off the line would have me thinking about fuel flow restrictions. A long grade demands a high fuel flow for a relatively long period of time. A fuel pressure test won't detect the problem because it is essentially a static test relative to high flow rates.

fuel flow restrictions?? wanna give me a alittle more than that? any tests i can run? what could posssibly be wrong. i replaced the filter, i put in a new fuel pump. the injectors couldnt be insanley giving up when under a long demand, could they? im so frustrated.....

-rob