Please help! I have a 2016 Alpina B6 with about 57,000 miles on it. Occasionally the car subtly bucks under the following situations: while coming to a stop at a light for the final second of travel; while backing up slowly like with parallel parking; at calm highway speeds (70-75 mph) and stepping on the gas a bit to accommodate for going up a gentle gradient. At first I thought it way just uneven wear of brake pads or rotors since it is most noticeable when coming to a stop. But it definitely happens when no brakes are applied. The bucking is not violent but usually lasts for 3-5 beats and is very noticeable to passengers. Everyone who has even been in my car has said at least once "what was that!" Some online forums have suggested that, with such a huge appetite for gas, at some point the car must have run near dry and damaged the fuel pump. There are no error codes. BMW techs have driven the car without recreating the bucking, though it happens very, very often. Does anyone have any thoughts? Thank you.
I have had this happen on a alpina before and it was the ignition coils starting to fail on the vehicle cause a slight misfire that the engine control module doesn’t catch to se a fault code. The other is the alpina uses a different range of spark plugs than a conventional Bmw engine and gets replaced more often. Might be time to replace the coils and plugs and clear the engine adaptations and see if that helps.
