1994 318i e36 idles rough.
Hi, I have a 1994 318i e36 BMW with a rough idle problem and flatspots when reved with backfiring through the intake system. Also the mixture is rich (black smoke) and there is no error check light illuminated on the dash. I replaced all the engine vaccum hoses, spark plugs and cleaned the icv but the problem is still present. I am open to any ideas.