My SA who is also the service manager and a friend called today and said PCNA 1st wants my stock exhaust put back on! I have a Sharkwerks side muffler delete exhaust. The mechanic who installed my X-51 kit in Dec '16 said at that time that my SWs would actually be great! But who knows. It was on for over a year with no stumble but maybe the lack of back pressure is causing fits for the X51 vario-cam system. So stay tuned some more! And I'm still hoping for a remanufactured PDK too!

 

That's BS. Grasping at straws. The SW is not the problem. It will be good for Porsche to see that once the SW is off, there will be not change. Good luck! I hate to hear about these unresolved issues.

 

Agreed that it's not the exhaust, nor is it the PDK. But by all means, let them rule things out.

I have an appointment with my local independent guy on Friday morning. I will keep everyone updated. My warranty is up in a few weeks, so I'm treating this as a PPI-like inspection to get a third-party assessment so I can go to my dealer with potential fixes under warranty. I mentioned the stumble was the big issue. Hopefully he can get to the bottom of it!

 

FWIW - I have a 15 GTS2 (3/15 build) and have no stumble. 3000 miles on it and it drives very well. FYI.

 

Good plan w the factory warranty running out! MY SA & the head technician seem confident that my car can and will be fixed! There optimism is encouraging except when I go here and see all the others who have not found a "cure"! I tracked mine last weekend and went through the PCA National instructor course and got certified which is awesome! Car ran great in Sport Plus mode Sat afternoon in dry conditions but on Sunday it was raining and I used strait Sport mode. It stumbled and hesitated several times! Really frustrating!
My stock exhaust is being installed as I type! Stay tuned!

 

Only 3 GTS4 cabs for sale in the whole USA. The Lava orange one in FL interests me the most! Also a GT silver one in OH but they want way too much! Stay tuned! Thx.

 

I don't think you will be disappointed with the GTS. Just a fantastic all around package. I have been following the market. Yes, the silver cab with ducktail in OH is way overpriced. Lava is great color but I don't like it with red calipers. Anyhow, good luck on either resolving your current problem or moving to a GTS.

 

The stock exhaust made zero difference except it is quieter! They now ordered a PDK valve body! Won't be here until tomorrow (Fri) and installed Monday. It won't fix it either I'm betting but at least PCNA & my dealer are chasing it! If I didn't like the build and colors of this C4s cab I'd dump it. But I absolutely love this car! Nothing else out there in my price range interests me! Stay tuned some more!

 

Glad to hear that they are trying. You certainly have had better luck that others, whose dealers have readily dismissed the issue as "normal". Your getting the stumble addressed and fixed will help a lot of other owners with finally getting their stumble fixed, I hope.

 

Indeed - not just my dealer, but PCNA also called it "normal". In fact I had a PCNA field rep come ride with me and said I was just moving my foot just slightly on the accelerator pedal, and that's what I was feeling (I'm not kidding).

 

Wow, that is so frustrating! I will admit that I sometimes feel my foot relax pressure on the gas now in "anticipation" of the damn stumble that is "coming"! I hate this! My Tech says they have never had one of "these" before but swears it is fixable! I sure hope so! A complete PDK replacement is where is he going. I keep looking at 997.2 GTS4s which are in my $ range! Or a '09 TT manual. Crazy? Probably would be hard to go back to those interiors!

 

The Honda technical representative told the arbitrator the stumble I had in my car was normal about 20 minutes before the decision was made for them to buy it back.

ChuckJ

 

Alright guys. Took my 991 into a local independent mechanic. This guy has done only Porsches for decades. Rebuilt my 1986 911 engine and transmission. Preps race cars for the local Potomac region PCA guys. I trust him with anything Porsche.

Here are his notes:

"Idle low and rough. Stumble around 2800 - 3000 RPM with light throttle. Recommend smoke test intake system possible vacuum leak."

And here is the work order description:

"Check over car, test drive to experience customer complaint. Found rough idle and stumble with light throttle at 2800 RPM. 3rd gear. Check car with scanner read out fault memory (all OK). Check live data, found fuel trim at idle off bank to bank by 1% (should be closer). Recommend check of intake system sealing. Possible vacuum leak."

First of all, I'm overjoyed that someone respected in this field found my car to be "not right" (those were his words). We spoke at length on the phone and when I picked it up. He really feels like it's a defect in the intake system with a micro leak, and because these closed engine systems are now so closely monitored and adjusted, any vacuum leak can really throw everything off with sensors and the system trying to compensate.

I have an appointment with the dealer scheduled for Monday where I will present this new information and insist they proceed with more diagnostics. I have a feeling they will say "no fault codes found" again, and I'll be in another fight with PCNA. I have gone over my service records and found I have formally noted this rough running problem on service tickets SIX times. So at least I have the paper trail even if they drag this out beyond my May 21st warranty expiration.

 

Good to hear someone found something! Now ball is in Porsche's court and here is hoping everything gets fixed finally!

 

Thx Stealth. I sent a copy of your post to my dealer. They have had my car for a week now. It is suppose to get a PDK valve body tomorrow. Maybe they should be looking for vacuum leaks! Good luck to us all!