Dear Scotty,
My Dad owns a manual 2008 BMW 328ix with close to 150k milage. While driving normally (highway and city driving) the car will occasionally buck. It feels as though the engine completely loses power for a moment. It happens regardless of acceleration or coasting, and we can't find a pattern to it. He's taken it both to the dealership and an independent Bavarian car mechanic, and they can't seem to find anything wrong. Any idea what might cause this?
Aaron
Fuel pumps that are wearing out will often do that
Fuel pump or a clogged fuel filter I would guess.
Can it really take more than a year for a fuel pump to go out? Fuel filter looked clear when I checked it. I'll replace it regardless. Apparently this has been happening since last spring and the frequency of the bucking hasn't changed much at all over that time.
I should have specified the above post initially, but as another piece of info,, in the last year he's put almost 15,000 miles on the car
It could take some time for a fuel pump to completely fail. I had a failing fuel pump that whined in my 1999 Tahoe for over a year before it finally failed completely.
Good to know! I'd always figured that fuel pumps go relatively quickly. If nothing else works, I'll tell him to get that replaced. Should that fail I'd have to chalk it up to BMW's crappy electronics. At that point, best to buy a different car... Research doesn't seem to indicate anything else besides what yall have mentioned here. Thanks for the input!!
Idk if manual transmissions have it but I know my car had a bad mass airflow sensor and would just randomly do the same right before it outright failed. But my car was a automatic and had a check engine light on.
I'll definitely clean the mass airflow sensor too. Good call there. Manuals do have it as well, and they do get gunked up over time. There is a mass airflow sensor cleaner on the market that works well. Scotty does a video on this exactly.
@Aaron Johnson personally I would just take it out and see if it runs, I mean check for error codes first if you can but if it's the mass airflow sensor it usually can be driven without it. I recently had a bad maf and took it out after finding out. I drove it home afterwards, it wasn't the most smooth ride, it didn't know when it was best to shift. But because yours is a manual you won't have those problems.
(Edit) drive only to make sure that's the problem and If so replace it with a OEM one or a high quality replacement.