I recently purchased a 2008 528i with 30k miles on it. I took it in for noticeable engine ticking at cold temps. The problem was confirmed and the dealer replaced the exhaust lifters which was supposed to fix the problem. The car was fine the first week or perhaps I didn't hear much because we didn't drive much. Anyway, the car now sounds worse than before. Cluncking like a diesel. Also, both before and after I took it in for this, I noticed a lot of black stuff landing on the rear bumpper area- obviously from the exhaust. I also noticed very poor gas mileage readings on the OBD, like 14.5 MPG.

Can someone familar give me any input. Anyone think all three above are related? Is the MPG normal on a 528i? The loner I had was a 528xi and got 22MPG.

I will definately call the dealer and take it back in. Any input appreciated.