95 90 Quattro, 75,000 miles. When I shift into 3rd gear as soon as I let out the clutch, the car seems to buck. it feels like something is either slipping, or like wheel hop. If I granny shift and ease into it slowly it doesn't do it. Mostly when I drive it like a rental.

It needs new tires. they aren't bald, they just might be a little out of round. And showing some signs of dry rot.

Many/most seem to believe it related to worn/torn transmission mounts. I believe it's tied into manifold switchover butterfly plates not fully closing between higher gear upshifts tho either "may" be influenced, affected or even aggrivated by the other.

I would check transmission mounts and vacuum reservoir and switchover vacuum diaphram for ease or operation and if it's fully closing EVERY time you let off the go-pedal even from only part throttle and not necessarily or "only" WOT.

What would cause, or fix the butterfly plates from not closing? We just replaced every inch of vacuum line 2 weeks ago. And it shuddered before the vac line job also.

another method is to pull 10-12" of vacuum with a vac tester on the reservoir and the vac diaphram and see if it holds or leaks down.

No vac tester then install a short length of tubing to reservoir and draw a vaccum by mouth then place against hole in tubing and see if it holds for a minute or two. Repeat at diaphram after drawing enough vacuum by mouth to engage switchover fully. Again hold tongue against hole in tubing and see if vacuum holds for a minute or 2.

You risk getting little 2-3mm "tongue hickies" but they go away in a day or two. ;-)

I'd say it's related to the butterfly switchovers. My car has been doing it for the past 80k miles, so really not that big of a deal in my book ;)

I always thought it was cause that was how she was meant to be driven :-)