I just took the engine (only 6 months old), harness, and ECU from my wrecked 88 bronco and put it in another 88. Everything ran great in the old one but now when I increase the RPMs over 2000 it jumps down 400-500 RPMs and back up again every 15-20 seconds. Over 3000 RPMs and it jumps up 400-500 RPMs and back down every 15-20 seconds. Fuel pressure gage reads 32psi KOEO, 34psi at idle, and stays at 34psi no matter what RPM i increase to. I've changed high pressure fuel pump, fuel filter, FPR, MAP sensor, cap and rotor. Tested the Intake Temp Sensor. I can't pull codes because for some reason my EEC connection does not work and my CE light won't shut off when the key is on. My thought is that something is making the ECU think its running rich and adjusting for it. I'm not sure where to go from here. Thoughts??