hello everyone, i just installed a 4.0 out of a 1997 i used the intake, front parts, and header from my stock 87 motor. i pulled the old one because of a rod knocking. it still had great compression but the bottom end was trashed. long story short the newish motor feels gutless. it has 88k on it. the old motor was very sluggish and backfired when it was cold. also it would accelerate slowly when i held the throttle steady like it had a surge of power. the 97 motor is the same way but no surge just the sluggish feeling. any ideas on how to fix this. it has new plugs, wires, cap, rotor, and a new belt. thanks for the help.
mark