The wonderful thing about forums like this is that even though this problem might only affect a small percentage of cars, people from different parts of the country can be aware of similar issues. It may be helpful - I'm just guessing here - if one person spearheads the effort to get PCNA to acknowledge and fix the issue, and writes a letter that says something like:PCNA can then (if they want to) pull up all of the warranty claims on all of those cars and see if there is a common link.

If that doesn't work, at the very least it may help should anyone in that group decide that they want to file a complaint with the NHTSA or God forbid, file a class action.

I'm just throwing ideas out there.

 

Unfortunately I am also one of those that has this problem. Same response from the dealer.....'operation is normal'. My previous Boxster S had the exact same issue, with the same response from the dealer. I upgrade to a C4S in the hope that power delivery would be smooth......no luck. Love the car etc etc.....but it's very annoying and once noticed it drives one mad with every outing in the car.

My solution will be to hand the car back after the lease is up and move on to something else.................

 

I suggest you ask your dealer to re-install the operating software that they did when they received the car. I had a problem with the indexing on the window and this solved the trick. I suspect there is something wrong with the cam timing mechanism.

ChuckJ

 

See post #42

http://rennlist.com/forums/991/82255...oll-out-3.html

 

@PorscheCrazy.

Sadly the majority of stumbling cars are 100% stock with no mods whatsoever.

In addition, the problem definitely developed after several 1000 miles.

Thanks all the same.

 

I have the stock exhaust and have this problem, so that is not the culprit.

 

I did not notice it so much in car when it had the factory base exhaust on it. Now that I deleted the center with a cross pipe, I did feel it under hard acceleration.

 

Directly from the Porsche website:

VarioCam Plus System
VarioCam Plus is a two-in-one engine concept for adjusting the intake camshafts and switching the lift of the intake valves.

The system first differentiates between driver inputs that typify normal, everyday driving and those inputs that demand maximum performance. The electronic engine management system then seamlessly adapts valve operation to the prevailing conditions.

This results in instant acceleration, extremely smooth running and an extraordinary level of tractive power, but with a comparatively low level of fuel consumption.

Two items stand out to me:

"Seamlessly, and extremely smooth running"

Unfortunately, my car exhibits neither.

 

I get sick to my stomach reading the problems you guys are having. My 991 will be out of the shop soon, and I'll soon be driving it. I can't imagine something like this happening to it after going through the purchase and fixing it up. I know all of you are in the same boat. If I start experiencing this, I'm driving right down to Atlanta and staging a boycott in front of PCNA's US headquarters. Any of you are welcome to join me!

Imagine what a PR disaster that would be with a dozen 911's parked at the front doors refusing to leave. The local/nat news would pick it up in a second!

 

Exactly I was thinking the same thing if this does not get resolved. Can you say CNN

Can get a lot of Porsches to show up if it ever came to this.

 

Can someone post a video clip of the tach when this is occurring. Thanks

 

This is why I think that there are issues in the electronic management system software. Has anyone tried taking it to the dealer and asking them to re-install the software that they put in when they received the car for delivery?

ChuckJ

 

Can't really see the tach doing anything unusual.

 

The RPMs don't drop or change. This is part of the reason why techs don't believe there is a problem. You also don't get enough audible change in the exhaust not to capture it in a video. It's annoying in the seat of you pants coming from the rear of the car.

 

There's nothing to see on the tach. It's something you feel. Maybe if the car were put on a VERY sensitive dyno you could get something... But it seems to be subtle enough that it's only apparent to the driver.

One interesting thing I have noticed on the tach, however, is a bit of a change of RPM at idle. I don't know if it's related to the stumbling up near 2500, but my idle seems to have gotten a bit more rough in the same time frame as the hesitation has been coming on. When I sit at idle the RPMs seem to search around a bit.