i have recently acquired a 325 1986 and it is in the tail end of an engine swap... i am having some issue diagnosing what could be wrong, i have only hints of what has been done...i do know the wiring harnesses have been changed out and computers have been changed also... i have a few ideas but wanted some knowledge from BMW savvy people. she will start and idle but she seems to be low idle, not sure, the tachometer isn't hooked up correctly. when i flutter the throttle i can bring the rpm up, and it seems to hold ok when it is up. if i try to gas without flutter it drops rpm and gets near to stalling. i have searched for a vacuum line broken and haven't found one.

i have been told that the idle motor can get gummed up and i should clean it. i have pulled it out of the tb area and have left the wire connected.. it closes and sits there and hums while its in run position.. is this a telltale sign of an issue or is this normal for this motor?

after cleaning out the idle motor with choke cleaner, i have a decent idle but if i accelerate quickly it still causes it to choke itself out. all wiring seems to be direct plug in minus a shoddy job on the o2 sensor. when the sensor is completely disconnected the vehicle runs the same as it does while connected the way they had it. i haven't found any brittle vacuum lines or any intake leaks.

i have noticed today that the air box/air meter may have not been changed out yet. is there a major difference from the 2.7 to 2.5 air meter, if i restrict air flow at box it accelerate fine and have full response with throttle. i have tried to adjust the air meter somewhat but to no real change.

i found my charcoal canister is completely missing and i am running the electric actuated valve. i have a straight line from tank to tb now. my idle is running better but i am still getting some pretty good air kickback under quick accel when not restricted.

Any help or new ideas would be immensely appreciated

anyone have any ideas?