I have a 90 lx 5.0 when i get on the car (full throttle) at 4500rmp it falls on its face and jerks, like im pumping the gas. this happens in all gears. If i gradually push the gas and come up to speed pass 4500 rpm then it doesnt do it. I just upgraded the engine with these upgrades- specs- holly systemax upper/lower intake, comp xe276 cam, noisy gear drive, flowmaster exhaust sierse 40 flowmasters with exhaust cutouts, mac shorty headders, 19lb injectors, stock tb, bbk 76mm mass air. Before i upgraded the engine, it ran horrible- when i got on the car it would for no reason go to idle and then run real choppy and gain power back. Im at a loss and need help/ My buddy has a completely stock one and took the throttle sensor off and tried that, but still no luck. tried stock mass air and it ran like it did when i got the car(horrible)