haha welcome to the club! I have replaced many things on my 318i and it still wants to get 18mpgs when it used to get more

. i have replaced the alternator, spark plug wires, spark plugs, fuel injectors, air boot, air intake housing, new complete cat back exhaust, new flex plate, new guibo, new timing chain, new belts, new knock sensors, new manual transmission, new rear bumper, new seats, new depo head lights, new hoses, new brake pads, new brake rotors, new brake lines, new H&r shocks, New sport bushings, new engine mounts, ETC. the only thing left i really have to replace is a crankshaft seal leak (which is really bad.) at the moment like i said earlier, i only get 18 mpgs as opposed to the 20-40 i used to get, the only thing i can think of is the leak? my advise to you is to take it to a garage that knows what they are doing and wont rip you off (not a bmw dealership) ! if it was up to the bmw (dealership) i would still be paying for the damn knock sensor which they wanted to charge me $1200.00 lmfao. My point is, if you have these engines running right they can acheive incredible Mpgs/speeds but if you have these engines running wrong they can cost you great deals of money in repairs & gas!! Take my advice repair every thing you can now! :cool: