So I'm looking or some help. I've got a 2011 6-speed that is making a strange suction noise when shifting up to third and fourth, presumably 5th, but at that point, I'm going to fast to hear it. It does not make the noise when down shifting, and there doesn't seem to be a noise when going into 2nd.

When the suction comes, I seem to loose a bit of throttle (1-2 seconds) and then it exhaust sounds fine and things are back to normal.

I thought it was a low RPM thing (between 1000-2000 RPMs), but when then are higher (2500-3500 RPMS), the noise persists.

Any thoughts?