ok will check the rear axles tonite.

Good idea on the undertray Kurt. It is one of the things I thought about this past weekend to check. The other thought i had was that it could possibly be some sort of aerodynamic effect - maybe a stall due to the venting in the front bumper or possibly the rear wing?

Rear wheel Balance?
Dirk

nope...same things happen even with other wheels on the car.

"Transient Vibration" - sounds like a Downtempo EDM band.

ed

Is it the deer bits hanging off the under tray?

When coasting, do you ever just put in neutral to take the engine, etc out of the equation?

Stop Me If You've Heard This One
 

Of Porsche's new joke:

What's the difference between Beer Nuts and Deer Nuts?

Beer nuts are $1.39, and Deer Nuts are under a frunk!

:lol::lol:

speaking of undertray...stupid question but did you check these / make sure theyre good and snug? last year i was black flagged (at VIR??) twice in a row because of "something dragging under the car". back in the paddock i couldnt see anything amiss under there so i went out again. only after the 2nd time flagged did my dumb brain decide to check more thoroughly - the leading edge of the middle tray had no bolts attached. looked fine and dandy at a glance in paddock but turns out it was bending down and scooping wind at speed.

if you have same issue, might be enough to cause vibration...

welcome back Martin. :)