Strange bang from MAF

[chevyfiftynine]

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.