Strange bang from MAF
 

A Porsche engineer told me I needed a new MAF on my 2000 2.7. The car had jerky acceleration and was making a mysterious intermittent muffled bang sound from the rear nearside when pulling away in 2nd or 3rd. He even fitted a temporary one and that seemed to fix the problem. When he put back the old one, the problems were the same.

I cleaned the MAF and that has sorted the performance issue, but the bang or clunk sound continues. The garage could not find anything mechanically wrong. I don't want to buy a new MAF when the car is running fine, and it might be a different fault altogether. Now I know where the MAF is, it seems to be coming from right there.

I can't see how the MAF could be making this occasional muted bang, but can anyone explain how this might be?

Thanks, Barry.

Possible intake backfire i suppose. Could be possible lean condition or timing issue. But are you saying that you are moving from a stop in 2nd or 3rd? My 3.2 doesn't really like starting in 2nd unless im already rolling. I wouldn't even try to start in 3rd. Hopefully im jumping to conclusions.

Otherwise did you check for faults? OBD II is your friend. Lots of codes for MAF.

possible backfire
 

Thanks for reply - it's an intermittent sound when accelerating in 2nd and 3rd, but not from a standing start. The intake backfire could be the answer - I think I'll have to buy another MAF and hope that cures it. What's OBD II? Is that a source for engine codes?
The car runs fine now, and that's the only annoying thing wrong with it. Regards.

OBD II is On Board Diagnostics 2. It is the standard that all vehicles sold in the US had to meet by 96. Through the use of a scan tool you can see relevant engine data and diagnose your issues possibly. I would recomend having the car diagnosed properly instead of just throwing parts at it. Could be anything causing a lean condition, not just the MAF. Vacuum leak, fuel quality issue, many more. just my $.02