dondoe87tatts

Ive got a 90 jeep cherokee 4x4 4.0L with a new rebuilt jasper engine that a few friends and i just installed, its the second engine we have replaced in this jeep cuz im jus a lil hard on em. But anyways, we started it for its first time in the new jeep, and it fired!!! wow thats a first lol, but anyways during the "fine tuning" part to get everything str8nd around and running right i noticed that it wont rev past 2000rpm while slightly on the throttle, it kind of acts as if it has a rev limiter but i kno that isnt the case, but if i punch it to the floor it runs like a raped ape, just like it should. lol it backfires and kind of "bounces" at that certain rpm until i open it up completely and then it clears up, but it isnt even driveable on public roads, wont go over 25mph without backfiring and sputtering unless i floor it and it runs puuuurfect idleing, weve tried rerouting vaccum lines, unhooked the egr valve, new cap, rotor, plugs and wires, its getting constant 32-35lbs of fuel pressure on the fuel rail while idleing or revving, new crank position sensor, new coil, new map sensor. the engine came from a 89 jeep cherokee, we havent tried swapping the computers yet, but the wierd thing is is that i can completely unhook every wire from the "throttle body", and it will run the exact same way, no change. idk where to go from here. HELP