Hey guys,

i know this is going to be wierd, here is the deal. My car, 1989 760ti would run for a while and i could drive it fine w/boost. Then you shut it off start again and the rmps go wild( 300-1500rmp) and then car stalls out. So i replaced the amm with a newsed(new to me but used) and the car would be drivable except under boost it would run way too rich and blow black smoke out the tailpipe. I then replaced the fuel pressure regualtor and the seals on the turbo-bypass valve. I also got a new hose for the fresh air intake and a new pcv thing(opaque white hose connector mine was so clogged and the little nipple broke of). OK so here is the deal, if i put in the old on I can drive with boost but then it just randomly goes crazy. However if put in the newsed one then i can drive it all the time except i cant let the gauge go to the white otherwise it bogs down and starts shakings and black smokes pours out the pipe. I'm soo confused and i dont want to take it to a mechanic but it seems very tempting now. ANy suggestions, this doesnt seem like an air leak because of the way the two amm behave diiferently

BTW both are the same model number(amm)