P2096 bmw 535i xdrive

Hello, At this point I always recommend seeking diagnostics. You don't have to use a dealer, but you may have already spent more on parts than diagnostics would cost. You are looking for a fuel system issue or clean air entering the exhaust. This could be a fault in the secondary air injection system, a vacuum leak, and exhaust leak, or a bad catalytic converter. Other issues could be causing it, but this will be a difficult issue to track down at home. Again, I recommend seeking professional diagnostic help.