Picked up 2012 with 40k miles. Great car, but when I accelerate moderately hard from a stop sign turning left, the grip surges between the rear wheels.
Its not just an issue of sand or gravel - it will happen on clean roads and tires.

Not as noticeable on right hand turns, but then again you can't give as much throttle on those.

I can't imagine this is a stock behavior from such a refined vehicle.

Could it be a bad rear diff?

No codes stored. Behavior is very repeatable.
The car just goes whump whump (no sound, you just feel that loss in force) with a noticeable slip in forward thrust when it happens. Nothing in the steering wheel.
Feels more like the rear tires than the front.

Never had a car (or truck) behave like this before even with AWD.

 

when u say "surges" , not sure what you mean.? Do you see the yellow traction light flash once or twice during this feeling?
Turn off the traction control and see what happens. Sounds like maybe its just that traction control responding to a wheel starting to break loose from the acceleration while turning. Thus the feeling of loss of force you stated.
This would be normal.

 

its psm kicking in , turn it off

 

Yep, was surging caused by the PSM kicking in.

Been driving lately with PSM off and I like the car much better this way.
its only a V6 and its AWD so I dont feel like its squirrely at all.

Wish it would remember the PSM off setting (as well as the Sport setting) every time I start it.

Thanks, and sorry for the silly question.

Even so, the PSM system seems very jerky for such a refined car.

 

I got the same thing in left turn accelerations from stop. Got beat off the line by a teenager in Dodge Charger Hemi for Pete's sake! The next time I came to that intersection late at night a few weeks later I was on a new set of tires, sport mode ON, and I didn't back off the gas at the first surge and it went clean through. I have a base, 2015 model, V6.

 

Once again in case you didn t catch this before...

 

I had a similar problem.
I took the car for a wheel alignment front & rear.

The alignment was way off on the rear, and it solved the problem

 

I have 2014 PAN4 with PASM. It is FINE acceleration and very smoothly in sport setting. You may need to bring your PAN4 to Porsche dealer to check it out. You should feel smooth and excellent traction. I was behind Tesla S90D on the curve at 100