I could use some help as this is currently my daily driver, lately I have been having an issue when I'm in OD with the TC locked up on the freeway, If I try and get it going any faster than 60mph I feel a lot of movement in the gas pedal(almost like it's fighting me, no joke) and a loss of power. This happened twice on the way home today and once a few days ago and the only way I could get it to chill out was to ease back off the gas a bit and keep it below 60 mph. Is this a sign of a clogged fuel filter? Is this craziness I'm feeling on the throttle cable just the engine missing and shaking around because of a lack of fuel? I didn't see it blowing black smoke or anything when it was happening so hoping this is an easy fix.
only around 10 lbs of boost and 650egts during this problem each time
first gen 91 5.9l 6bt engine swap no tachometer
stock h1c turbo with no intercooler
stock head bolts
Denny t fuel pin and boost spring
KDP fixed
fuel pin and boost reference spring installed in the fuel pump
3.75" exhaust, no cat or muff
stock injectors
47rh automatic transmission with TC switch and OD switch on dash

Let me know if you guys have any ideas! Thanks

 

Replaced the fuel filter on the side of the engine, still having the same issue
It cruises just fine around town, and no issues at 55-60mph.. once I give it more throttle I feel crazy vibrations in the gas pedal and a loss of power till I back off the throttle. Is this the lift pump going out? Anyone?

 

brand new lifter pump installed today, still has the same problem, engine starts stumbling at 60+mph
Any thoughts?

 

sounds like your hitting the gov. weights in the injection pump..thats were i would start my investagation....scott