mtony

Maybe Porsche doesn't want to admit a problem because it's all part of their effort to pass emission tests a la VW!

Zonian

Interesting article here re Porsche software to limit exhaust noise allegedly causing stumble:
http://www.dailymail.co.uk/news/arti...ty-report.html

STG

Very interesting ....

"Another Porsche owner called Nick Ray suffered the same problem but was allegedly told by a dealer that it was a common characteristic of the car type and there was no fix."

^^^ sound familiar??

mikemessi

Well. Not sure if this is the root cause of everyone's problems and maybe there is more than one thing going on but I would think an after market ecu flash would solve this?

duxsi

Wow - Whatever shred of credibility this company had left regarding honesty, just flew out the window.
Their compulsion to blatantly lie at every turn clearly dates back several years and apparently knows no bounds. Not even when it relates to road safety

The news article is shocking at best and once again confirms what many of us have suspected for a very long time.

997s07

The 996 TT, 997.1 TT, and 996 / 997 GT3 (RS) cars all have an engine that blows it's coolant lines and spills coolant on the ground. A lot of cars have been affected and a few people hurt. Porsche doesn't give 2¢.

neanicu

The more I'm reading on this issue the more I tend to agree that this drivability issue can be corrected through a software update from Porsche. My only concern at this point is why does it only manifest on certain cars and not across the board... Very puzzling!

Archimedes

If that article is accurate, it would seem that Porsche can't offer a software solution without putting the car in violation of European noise standards. So basically, Porsche knowingly used a software trick to meet sound regs at the expense of drivability and they're telling owners that doing such a thing is perfectly normal and acceptable. Kinda sucks, but I don't think they're alone in this, though I'd bet that most of the lag issues people experience on other cars has more to do with automatic transmission software programming done for fuel economy reasons.

Larry Cable

That was my initial thought also, although it seems that people have had
re-flashes and this does not rectify the problem, so I dont think that's the
root cause, but its the ECU learning that is manifesting the side effect

given that it appears across a variety of models, I dont think its model specific, which then leads me to think that it is probably related to a particular component shared across variants engines ... something that the
ECU (in)directly monitors and can manipulate

I would start to correlate production dates for the cars experiencing these problems in case there is a batch of common components installed in those
cars that is out of spec and thus causing the ECU to mis-learn ... or perhaps
the ECU itself.

I might also try an aftermarket flash such as GIAC or EVOMsit etc to see if any changes to the maps would eradicate the symptoms (but I doubt that
is very likely)

Larry Cable

another thought; what about trying a SprintBooster? Since these fool the ECU into thinking the accelerator is being pressed faster/harder it might "lessen" the duration of the stumble?

duxsi

Larry,
We also polled the affected car owners about their production dates to determine if there was a correlation to a bad batch.
Nothing at all with dates being all over the place.

A user installed the Sprintbooster for a while, and that only gave the sensation of being in Sport+ all the time. Didn't alleviate the stumble.

IMHO, the fact that this also happens when using cruise control eliminates the pedal / potentiometer theory.

GraphiteGrey

Here is a Rennlist thread that discusses this issue. The thread has a video that illustrates the problem that is the subject one of the investigations referenced in the complaint:

https://rennlist.com/forums/996-turb...ty-report.html

Here is the appeal discussed in that article:

http://www.informationtribunal.gov.u...(04.08.15).pdf

Here is the ruling for that appeal:

https://ico.org.uk/media/action-weve...s_50527543.pdf

Here is a Piston Heads thread regarding the issue; note comment 3 on that page by Chris944 which nicely summarizes the appeal document.

http://www.pistonheads.com/GASSING/t...071.01626&nmt=

Money2536

I'm so sorry to hear this issue is still prevalent. I decided a year ago in September/October '14 to take the $30,000ish loss on my X51 C2S and get my GT3. I know how frustrating this is to have no one a Porsche listen to you and simply think you are crazy. Good luck all.

beaverlake

I've been reading about this here and on other sites for over a year. I "think" I had a very slight stumble on our 2012.5 launch 991s, but I've made a point of driving the 2014 C4s in the suspect rpm range at both "cold" and "warm" motor temps and this car has zero stumble or hesitation. So I'm as confused as anyone. Two cars, same drivetrain (PDK, sport chrono, etc), same drive modes (normal, sport, "manual" shift) with noticeably different drivetrain response characteristics that as far as I can tell should have no relationship to 2s vs 4s.

one-rennlist

Wow, this is scandalous. I have the same issue with my 997 GTS. My dealer replicated the issue with a different 997 GTS but said they could not fix it. I will print out this article and hand it to my dealer Monday morning. This needs to be adressed!