ignition misfire

[riverat440]

My source of aggravation is an 88 325i. Upon replacing the engine with a used 85 engine I have developed an ignition misfire which I have spent countless hours trying to correct. I transferred all of the electricals from the original engine as it wasn't a motronic 1.1. Also changed the plenum and associated hoses in order to have it match up with the wiring and hookups in the vehicle. It has new Bosch standard plugs, cap, rotor, coil, and wires are Bosch not new but in very good shape. I've checked the gap and resistance of the crank sensor also and are within specs. Also checked the coil, it is OK. Double checked all of the electrical connections and made sure there is a good clean connection. All of the relays have checked good also. Removed the control unit and made sure there was no water in it and the harness had a good connection. Now the problem, the engine starts fine and idles OK but when you give it some throttle it stumbles terribly and dies. If you feather the gas pedal it will accelerate buthas a definite miss at all RPMs. If you hold it at any given RPM for a while it does smooth out after a while. I put my high voltage spark tester inline between the coil and the coil lead to the distributer and it flashes off every time that the engine misses. It is as though someone is flipping a toggle switch feeding the primary side of the coil. It is a random miss not like a fouled plug. It has me about half crazy as I have checked and rechecked all conections and terminals that were loosened during the swap. Any suggestions are greatly appreciated as I am new to BMWs but have never been stumped for long before and have almost 35 years working on every other kind of vehicles including the electronically laden late model american brands. Thanks in advance, Rick.