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What is the current state of the 'engine stumble' issue?

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Old 08-01-2018, 03:25 PM
  #241  
Nin Din Din
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Originally Posted by stealthboy
Most of us spent the time on the 6speed thread, so you'll find a lot of good solution attempts there. My dealer also "reset" the software so it could relearn, and I swear it felt better for a day but returned right back (even with my driving it like I stole it to get it to learn differently). A lot of folks just tell me to sell the car and get another one if it concerns me so much but I refuse to because 1) I am confident this can be diagnosed and solved, which is why now that I'm out of warranty I'm having independent mechanics look into it, and 2) this was a build-to-spec car I ordered and then picked up at the factory. It also was the result of a very special moment in my life that let me be able to buy a new 911. So I have a strong connection to this particular car.

Anyway, thanks for the detailed write up. Please continue to keep us up to date. We're all in this together!

Edit: By the way, it's not a PDK thing. Mine is a 7MT.
Stealth,

I read your saga. If it were me, I’d be on pills by now. I don’t hold out hope with Porsche on this. There are plenty of complaints over the years and these guys don’t want to admit that there is an “issue”. They know it’s a flaw that can be corrected, or maybe it can’t be permanently corrected within a limited prescribe cost to Porsche. I thought by going to the local dealer and perhaps later going to the selling dealer I could establish that I recognized the problem and took appropriate steps. If later on, someone somehow turns an arbitration complaint into a class action, I’ll have a place holder so I can join the class. Chances are I’ll win the lottery twice before that happens.

The thing that frosts me is, it’s partially my fault for not performing due diligence in researching this before I traded my 997. After all, you guys were well into it before I put my money down. That coupled with the thought that Porsche must have known this was occurring but apparently took no steps to prevent it going forward,

Porsche experience. Where’s the dam Christophorus reporter when you want him?
Old 08-01-2018, 03:35 PM
  #242  
Nin Din Din
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Originally Posted by Dewinator
Weird like I’ve said before, mine stumbled hard when the throttle body was giving out but since then no stumble and I have 83k miles on it now.
i read that you had replaced it out of pocket but by then the car was throwing codes. I thought you posted later that had cleared the stumble substantially but not totally. No? The thread was so long I can’t remember.
Old 08-01-2018, 09:30 PM
  #243  
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I feel a "stumble" only when in auto mode with the auto start/stop function engaged. If I accelerate and let off the gas and then quickly accelerate again, on occasion, there will be an unsettling "stumble" where it takes perhaps a half second to a second for the transmission to engage and for the car to accelerate. It is almost as if the transmission is in neutral when I apply the gas (even though the car does not rev when the "stumble" occurs). My theory is that the transmission is "confused" by what it should do for a split second - it drops the revs automatically with the auto start/stop function on. Thus, when I release the gas, it drops the revs as per the auto start/stop function but if I quickly reapply the gas, the transmission needs a half second or so to catch up to my foot's order to accelerate. Hence, the brief lag. I have never had this problem in sport mode because - at least according to my theory - the transmission does not drop the revs for fuel efficiency when the foot is taken off the accelerator.
Old 08-02-2018, 08:25 AM
  #244  
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I can't remember if I updated this thread with my last experience. I sold my 991 with my stumble issues that resolved themselves (sold it for other reasons) and bought a used 2014 Bosxter S (3.4 I believe). It stumbled pretty badly, so I brought it in to the dealer. The lead tech drove it with me and acknowledged the problem by stating "they all do that". Well, of course we know that's not true. He then said "most owners don't drive them hard enough, so every time we have them in, we run it up to redline" and he demonstrated what he meant. He didn't do it in an abusive manner, and on this used car I didn't care. But holy moley if he had done that on my 991 while it was still in the break-in period, I would have been one annoyed customer! One would hope that they pay attention to the mileage and act accordingly.

Sorry for the digress. Anyway, the performance of the 981 annoyed me enough, and with prices going up with the announcement of the 718, I got rid of it too.

Now every time I think about buying another Porsche, I think of this thread.
Old 08-02-2018, 11:15 AM
  #245  
Penn4S
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It is really disappointing that you have this experience with the brand. I am on Porsche #13 and really have had amazing experience with the brand. I had an issue with a 996TT with the "pop out of gear issue" and Porsche replaced my tranny in 4 days with a new full tranny warranty. I have been fortunate to have just a great ride in the many versions i have owned and it is really sad to see how you and others have been frustrated by issues that should have been taken care of.
Old 08-08-2018, 12:55 PM
  #246  
Nin Din Din
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My car is back from the dealership. In summary, the car remained at the dealership for 8 days. The service manager and tech all danced around admitting they could feel the surging vs. just seeing the tach fluctuate. They would not call it a “problem” or “issue”. One service writer off the record admitted that to call it an “issue”, “defect” or “fault” could lead to warranty car replacement demands if the issue cannot be resolved to the customer’s satisfaction so they err on the side of protecting the dealership and Porsche. No kidding?

The service tech (supervisor) test drove the car several times. The service manager drove it as well, first admitting that he could feel the surge, then reversing himself and saying that he couldn’t feel it so much as see a slight movement of the tach. They sent the car’s “values” to PCNA in Atlanta who replied after 3 days that the values were “normal.” They then reflashed the PDK and also reflashed the DME. They test drove another 991.1 for comparison. They admitted the comparison car had the same issue only not as “pronounced.”

They say since the car is running “normally,” according to Porsche, there’s nothing else they can do. Wonderful.

It’s been too hot and humid to muck around with the car. However, on my way home from the dealership I did noticed a barely perceptible stumble around 1900-2000, and to be honest, I really had to search for it and couldn’t produce it in consecutive tries. Perhaps the reflash straightened it out...until it learns how I drive.

When’s the next support group meeting?
Old 08-15-2018, 12:19 PM
  #247  
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Having read a number of threads of fuel smells in the cabin and at least one person's car going to limp mode due to pump seal failure, I wonder if the fuel pump isn't maintaining suitable pressure throughout all load conditions. Maybe just drooping a bit when demand is suddenly increased, not enough to code just a temporary plateau. I don't believe it is a software issue due to folks having software updates or aftermarket coding and the problem remaining, I don't think its the PDK as it seems to occur in both MT and PDK. Its an interesting issue....
Old 08-15-2018, 12:48 PM
  #248  
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^^^ It’s an issue Porsche doesn’t want to touch, especially since no codes were thrown.
Old 08-15-2018, 05:57 PM
  #249  
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I'm curious if this issue rampant across all 911's or just certain ones as I have a 911 on order for October delivery and after reading this thread I am very concerned.
Old 08-15-2018, 06:19 PM
  #250  
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Originally Posted by Lo911TTS
I'm curious if this issue rampant across all 911's or just certain ones as I have a 911 on order for October delivery and after reading this thread I am very concerned.
Yous will be a turbo car. I do not believe that any of the stumble issues were on the 991.2
Old 08-15-2018, 07:36 PM
  #251  
chuckbdc
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This issue is not rampant- it is exceedingly rare.
Old 08-15-2018, 07:39 PM
  #252  
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Good to know thank you for the info.
Old 08-15-2018, 08:00 PM
  #253  
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Interesting to discover this. I have been driving mine since 9700 miles when I picked it up and am now at about 13k miles. I assumed it was something due to my plugs/coils since I believe they are the original ones due to the maintenance records I received with the car. Bought new coils and sparks and planned to put them in. If I still feel the hesitation afterwards then I guess I am in the same boat as many other owners. Car runs great and new lights or messages on display. Any newer info pop up?
Old 08-15-2018, 10:01 PM
  #254  
cpbmd
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Nice avatar. I have the same 2013 911 white on Luxor Beige. 7 speed. Bought it 2 months ago. I already put 2000 miles on it. No stumble thankfully. I got to change my avatar.
Old 08-16-2018, 10:15 AM
  #255  
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Originally Posted by cpbmd
Nice avatar. I have the same 2013 911 white on Luxor Beige. 7 speed. Bought it 2 months ago. I already put 2000 miles on it. No stumble thankfully. I got to change my avatar.
Thank you!

Mine is the same color combo and 7 speed as well. Sounds like we got twins right around the same time too! haha


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