Hello everyone. Do these stumble/hesitation issues extend to the turbo cars or just the n/a cars?

Has anyone had a similar issue with a 991.2 now that they have new turbo engines?

 

2009 C2S 102K miles Manual Transmission. Saw this thread via search engine..... As I understand it, this issue surfaced with the intro of the DFI engine in 2009 and, in particular, on S models. I have it. It pisses me off. It has been consistent for 75K miles of my ownership. It usually hits at 2700 RPM but higher is I am more aggressive.... If going up a slight incline, the car actually jerks. Gear is irrelevant and I can do it at highway speeds in any gear... take foot of gas, let speed drift down where RPMs are around 2K, then add the gas.... JERK. I added the sharkwerks X pipe and it became audible: with the windows down, I hear a slight "Pshht" sound like a turbo waste gate. Pisses me off. A Porsche tech on the PCA Q&A suggested it was the variable lift and that flap in the intake plenum (only on S models IIRC) that are actuating at the same time. He heard of this issue but no answers. My dealer experienced it with me and said he heard of it too, there is no TSBs, so "keep an eye on it".. great. Jeff over at RT said I may have a "lazy actuator". I get no thrown codes. Anywho.... me and a few fellow RLs with 2009s with this issue are about to start collecting Durametric data. Any tips on collecting this data such as using the tool or exactly what to track in Live Data would be appreciated. I don't come over here much so maybe ping me over at RL. http://rennlist.com/forums/997-forum...-actuator.html Peace Bruce in Philly

 

You have a lot of patience. I'd just trade the car. My daily driver is a 2013 5 series. Intermittent door lock problems, rubbing sound on light brake application and a whistling sound on light acceleration from a stop. None of these issues have been fixed in 3 visits to the dealer - no fault found. I have 3 companies I operate and travel every two weeks. I have a young family so time is always at a premium so I don't have time to keep running to the dealer. They can just have it back in 4 months when the lease is up and I'll move on. You'll never get to hesitation issue fixed by PCNA and quite frankly, the car is almost 7 years old and Porsche has moved on from that problem in newer genration power trains

 

I second that, it's one of the things that pushed away from my already missed 991s. PCNA is so clueless that the SA told me it's an inherent problem with the PDK, clearly not the case above.
I had a beemer with chronic top leaking, unfixable by the stealership... I guess eventually all of us will have an ulcer making car story to tell. Ignorance is bliss, drive a Camry then...

 

2016 S
built 9/15
PDK
No power kit
1500 miles
DME update 1 week ago
stubble remains at
2200-2900 rpm

 

It is not a PDK problem. I have a 7MT 3.4 991 and have the hesitation. 2013 911 Carrera built April 2013.

For me there are two different stumbles. One is a constantly-held mid-to-low throttle at 2100-2300 RPM. It's more of a hesitation like one would get with bad gas. The second is a larger stumble at 3K RPM when accelerating through there (VarioCam plus change point). But lately I've been noticing it more through the whole 2200-2800 range under moderate-to-heavy acceleration. I keep wanting to think they are different issues (hesitation at lower rpm vs. stumble right at the variocam transition) but I think they may all be related at this point.

At this point I'm trying to be patient until May 2017 when my warranty runs out. I will then seek the assistance of an independent Porsche mechanic in my area. I've already talked with him about the issue so we're forming plans now for a diagnostic process.

 

This must be one of the latest stumblers on record. (Built 9/15).

 

I have a 9/15 build and took delivery 11/15. My car was not used much during the winter after delivery. I installed the COBB Accessport pretty much right after the break in. Recently, I had to bring my car in for warranty work and removed the "tune". I drove the car a couple of days and there was a noticeable stumble after the "tune" was removed. This stumble mirrored what has been written about for years. While the car was in for servicing, an ECU update was performed. The stumble was a bit less but still there. I drove the car for a few days and the stumble was present. I reinstalled the "tune" this weekend and the stumble is now gone. I can't guarantee that it will be a fix for everyone, but it solved the issue for me.

 

COBB only shows the accesport for the 991 Turbo. Is you car a Turbo?

 

Not sure where you are getting that information. My car is 2016 3.4L.

http://www.cobbtuning.com/2016-porsc...rera-pdk-wm-s/

 

I see it listed. Just need to dig a little.

 

Since seeing this thread wake up, and the stumble was more on my mind, I was able to observe a few things last night that I found interesting.

1) I drove to work. The car sat for 10 hours. Then I drove home, but I had to stop and run a few errands. I noticed that the immediate drive leaving work had the stumble, but once I stopped and let the car sit for five minutes, it did not seem to stumble at all the rest of the way home. Seems like a drive after being off for a while has the stumble, but warm it up, turn off the car for five minutes, and then it's better.

2) My car doesn't really seem to stumble in 1st gear at all.

Still holding out hope that it's software/sensor related.

 

I see that this thread has been quiet for a few months. I just registered on 6Sonline in order to post. I want to share my recent misfortune with the members here. A short back ground first. I have owned 7 911s including my current 2013 C4s cab. The first 5 were manuals, the last one before this current car was a 2010 C2s w PDK and SC. I have enjoyed them all. This 2013 I purchased preowned with 13k miles on it. It was very nicely optioned and in colors I really liked. For various reasons and the fact that I'm nearing retirement in 4-5 years and purchased a small farm (not paid for yet), I decided I would keep this one long term. I owned a 2007 C4s that had the X51 package on it. I decided to have the X51 power kit installed on my 991. The dealer head mechanic did the job over two weeks time in Dec '16. After the required and highly recommended break in period of 310 miles (500 km) I discovered I now had the dreaded "stumble"! I can't "make it do it every time or predict it" but it occurs as the others have said around 3k rpm. Do I like the X51? Yes, but if I had known I'd get the stumble you can bet I would of skipped it. My dealer is aware but has no fix or comment. I would consider selling it but can't in good conscience do this. I could trade it at a Porsche dealership with no guilt! But I like this car and everything about it EXCEPT the occasional stumble. What can or should I do? Live with it? Does anyone think there will be a fix? The RMS/IMS bearing issue never really got a factory fix but they did get Class action relief, right? To get it repaired from indy mechanics per L&N engineering I think? TIA, Rob in Louisville, Ky

 

I don't think anyone has resolved this. If you sell the car you'll get nothing for the X51 you just added to it. Maybe the extra power makes up for the annoying stumble?

 

Not sure I agree. I won't get even half of what it cost and I knew this going in. But the Power Kit will always bring a premium to a few who really want the best NA non GT3 engine you can buy. But not with the stumble!! The intake sound alone is intoxicating over the stock sound. And in Sport Plus mode this engine utterly sings to redline. The time to redline is amazingly faster than the stock engine. A dealer would recognize the "upgrade" as well but of course low ball me. I see several GTS4 cabs for sale but all have alcantara interior which also means no ventilated seats! I like mine a lot! I'm going to contact my attorney and consider class action if it has not been started yet. He works for (free) beer for me.