Is this happening in all modes i.e. normal, sport, and sport+? I haven't noticed this at all on mine. Ill have to check it out today.

Money, I'm sorry you've joined our exclusive Hesitation Club.

In my extensive, careful observation, I have two modes of hesitation/stumble.

1) Driving at a constant RPM 2300-2500. Trying to maintain constant speed. It's like a fish tugging on your line - a slight hesitation that comes and goes like there's water in the fuel or something.

2) On more medium/hard acceleration up through a range, I get a big stumble at 3000 RPM. This may be related to the VarioCam repositioning.

Seems to be the same on normal or Sport modes.

I have at least had my tech acknowledge he felt something when I went on a drive with him. But that's where we stand. No codes = no repair. I could tell he felt for me. He tried updating the software (no change) and fixing a spacer on the flywheel position sensor (unrelated, but he was just trying things). He called the regional PCNA tech rep to see if he'd seen anything else around and no luck there.

I think more of us need to raise this up to PCNA. My next course of action is to take my car to a different dealer and basically tell them "drive this car and tell me it's normal". After that I'll be contacting PCNA directly.

Yes all modes for me. It started at about 4,000 miles and has gotten worse with mileage. I'm at 4,600 now.

The fish tugging on the line is a great analogy of what I'm experiencing.

One difficult part for me is that the dealership is a good hour and fifteen minutes from me. I know I'm going to have to commit the time and effort to get the car there multiple times before I can start kicking and screaming. I'm going to print this entire thread and the ones I can find on Rennlist to take with me. I guess I should involve the dealership management as well.

Good luck Money! What a pain...

If PCNA doesn't acknowledge the issue, the dealer doesn't get paid to fix it correct? The dealer won't go out their way if they don't think they'll be paid for it I assume?

That's why it starts to make sense to threaten "lemon law" and make it clear you will be very public about it.

Those that read my Journal know I'm slightly detail oriented, so I'm committing my every waking moment to getting this fixed. This dream is very quickly turning into a nightmare.

Alright, I just printed and highlighted about 100 pages of the multiple threads from this forum and Rennlist for my appointment tomorrow. I called the Sales Manager to let him know about the problem and make him aware I'm coming. He is super nice and threw out the "whatever it takes" to make you happy comment. My salesman, a super knowledgeable P-Car guy, is going to be there as well.

This time I'm going to do the driving first with the Service Manager in the car. I let the tech do all of the driving at the other dealership. I need to show them what is happening and then let them experience it after demonstrating.

I'm hoping it's going to be all hands on deck. The Sales Manager threw out the idea of them buying the car back from me, so hopefully we don't need to go down the lemon law path. This may be a quick 6 months of ownership and then into a GT3. We'll see. I'm just not interested in this version of my beloved C2S. The bucking, stumbling, and hesitation is just too pronounced. I can't live with it, but I'm not interested in losing $30,000 in 6 months.

On a side note, I put a call into Tom at Champion to ask him about GIAC software. Certainly, it wouldn't help my warranty case. If I can't come to some sort of fix or resolution and I'm stuck with a stumbling $135,000 car, then I might give it a whirl. Maybe I can take up a collection and be the guinea pig. :D

Get in line on the collection. I'm the guinea pigs daddy, so I get to go first!!!

Best of luck, and please keep us all informed. I have visited my dealer three times about this so I feel like I've worn out my welcome over this issue. Definitely a good idea to have the service manager drive while you're in the car. Do a swap so you drive and he drives. Having my tech drive with me in the passenger seat was the only way I got him to acknowledge it. Even then, later in the day when I got my call, it was still declared "normal".

Also, tell your service manager to start communicating this back up to PCNA. That's the only way it'll help everyone else here. That way next time I go in for this issue and my service guy contacts PCNA, at least something starts to coalesce.

Godspeed. I'm rather selfishly hoping you have a positive outcome so I have more leg to stand on in my fight!

Good luck Matt. Hope it all gets resolved for you and that they find a solution so that other owners with the problem can benefit as well. Luckily, I do not have the problem (and hope I don't get it), but know how frustrating it can be.

Do it man. I'll contribute to the cause. If that software fixed the problem and added some HPs... A man can at least dream.

I'm already pretty sure I know how this is going to go. The dealer promising me they are going to take care of me, the service department is going to say everything is fine, I'm going to go back serveral more times complaining about it, I'm going to hire a Lemon Law attorney, then maybe Porsche NA will do something about it.

This is going to suck!

The biggest problem we face in attempting to resolve this problem is the fact that the dealers have apparently been well schooled by PCNA.

a) Do not admit that the stumble/hesitation exists.

b) If forced to admit that the stumble/hesitation does indeed exist in some vehicles, assure the owner that it is completely normal and that all cars do it. (Perhaps the best course of action would be to find someone in your area that has a car with no stumble and have the dealer drive the two back to back). So much for "they all do that sir."

I guess it then becomes a matter of precisely how bad the stumble is. I'd be willing to venture a guess that no dealer has ever determined one to be excessive.

My comment to them will be, why didn't it do this for the first 4,000 miles?

Very best of luck... I know how much you covet your car... I have a minor stutter with all the same symptoms but mild.... I hope for so many on here you get a fix, not just an excuse. I'm guessing the reluctance to acknowledge the problem relates to their warranty bill, not their technical expertise... Apparently the GT3 debacle cost circa £120m ... Enough to challenge even Porsches P&L!

My gut tells me that PCNA is very aware of the fact that some cars do indeed have a problem with the stumble. My gut also tells me that PCNA will do everything in their power to sweep this under the rug and avoid a potentially costly fix. For how many years did they refuse to admit to the IMS problem?

Start posting it on PCNA's Facebook page :p

All in good time Grasshopper.
First you must learn to snatch the pebble...

I'm back from the dealership 3 hours later. It's fixed!


Just kidding... It went even worse than I had planned. When I got there the service advisor immediately started arguing with me as I attempted to explain the issue. He said they weren't confindent in what the other dealership did, so they wanted to do the same thing. Scan for codes, do a DME update, and spot check. I tried to explain they would be wasting their time. As soon as I referred to my research, they immediately dismissed "the internet." I wised up an started referring to all of you as my "friends." Non-enthusiast employeed don't understand us.

So I went for a ride with the Service Manager. Super nice guy, but I could tell he thought it was normal operation. He just wasn't saying it directly to me. I'm driving in 8:00 AM Orlando traffic, so it was very difficult to demonstrate.

When we get back, he leveled with me. He said he'd be happy to chase this rabbit (within limits), but when he compiles a log pulled from the car to email to P-Tech, the first thing Porsche is going to ask about are aftermarket parts. He suggested before we do anything I need to get the factory exhaust back on the car. I agreed that made sense other than the fact that dozens of us are having the same problem. I didn't argue the point and understand the reasoning.

We decided it didn't make sense to leave my car to do the normal checks. I may be making the wrong assumptions, but I don't think he really thought I had a problem. I think he was just hearing me. I didn't get the sense they were going to spend too much time on it. So there is no way they are going to figure out the problem.

I drove the 55 miles back home with my tail between my legs. So a waste of 110 miles and 3 1/2 hours of time. I'm trying to not let this steal my joy. My temporary solution is to drive in Sport Suspension mode all of the time so that the stiffer setting and bumps in the road mask the shudder at bit. I guess I'm going to try and avoid 2,000-4,000 RPMs as much as possible. I don't think I'm going to last long with this one. I may beg the dealer to buy the car despite them not thinking there is a problem and eat the $30K.

My hands are thrown up in the air is disappointment...

I'm not sure what I'm going to do. I could easily put the factory exhaust back on and drop the car off. I just don't think they are going to do anything.

I decided to just ignore it. It's clearly something they can't acknowledge, let alone fix. If I get too annoyed about it, it will just destroy the enjoyment I otherwise get from the car.

Bummer. I have a few thoughts:

- before giving up, take off the exhaust and give them a chance to fix it.
- talk to the sales guy and see what they'll do for you.
- trade it on the M3 whenever it gets here. At least you'll save the sales tax.

If they don't perceive a problem, then it's likely that the used car manager won't either. Those guys never drive anything easy; he'll jump in and hammer it, enjoy that loud exhaust and then offer you wholesale.

Best of luck!

Here is what I would do.
Leave the car exactly as is and take it to a reputable tuner.
It has NOTHING to do with your exhaust and we all knew that Porsche along with their minions would (predictably) throw the aftermarket exhaust on the table as a possible culprit.

My car is 100% stock. Perhaps my toll pass is causing the stumble!

Just as Nick Murray's smoking, leaking, stalling car was apparently blamed on his radar detector, the Technical Service bulletin for a damaged wiring harness for his model year was never acknowledged / mentioned.

You have nothing to lose with a tune.
30k is a lot of money (by my meager standards) and driving more aggressively is not an option. I certainly don't intend to do 40 mph in 1st gear in my neighborhood in order to avoid the stumble.

A tuner will at least be willing to address your problem.

That is my next course of action.

Or, call your regional PCNA rep.

I think it's a waste of time dealing with the dealer. I'd keep your exhaust on. Anytime you bring up anything related to the internet they act like you're trying to convince them that aliens exist! I'd start doing some research and reaching out to independent guys that work specifically on Porsche. Did Champion ever get back to you? I'm sure this issue has to be familiar with the guys that actually know what they're talking about. Don't give up on your great 991 so easy.

The Porsche dealers don't have a clue unless their computer pops up an error message. They couldn't trouble shoot low tire pressure if they didn't have a sensor to tell them the tire looked flat!

Sorry to hear things didn't go as planned. The bottom line is that maybe we have to learn to live with the stumble. It's tough though, as you know, because once you experience it you're continually aware of it from then on. I'm so used to it by now that on the rare occasion when it doesn't stumble it perks my attention.

The sad truth is that the hesitation/stumble is real on some cars, although it varies in intensity. I'm still amazed that it won't trigger a code. (Of course, Porsche has probably programmed the OBC to accept the stumble as normal operation).:)

I will say it again - The fact that this problem does not occur in all 991s and seems to be somewhat random would suggest that it's NOT normal and a fix to replicate the non-stumbling cars is out there.

For those who are not sure if they have the stumble, trust me when I tell you that you'd know if you had it. It's not something that you have to look for.

Perhaps a forum poll might be in order?

I just got off the phone with Tom @ Champion. He said he wasn't aware of the problem we are having. I asked him his opinion on getting a GIAC flash tune. Natureally he said if it was his car, he would want to diagnose the problem before creating another one by tuning the car.

A possible test can be to pay a GIAC dealer for their time, get the car flashed, drive it for a few days, and then have the flash removed. I don't think the record of the tune will be wiped clean. But it could at least test to see if aftermarket software will fix it.

Sorry you did not have a good visit with the dealer, but I can't say I'm surprised. They have no incentive to chase down something when they can just declare it normal and tell there are no codes. That means less work for them and they can move on to more overpriced oil changes.

All,

Austin from GIAC was kind enough to provide me his thoughts on a GIAC flash tune improving the problem.


I Wrote:
I talked to Tom @ Champion. He suggested I contact you to inquire about a DME flash on a Powerkit equipped car. Is there a flash available that is specific to the Powerkit cars?

The main reason for my inquiry is that 991 911s are having an undiagnosed hesitation/stumble from 2,500-4,000 under light to moderate acceleration. There are a few dozen of us on Rennlist and 6speedonline getting together to try and figure this out. My hope is that your flash tune could fix the problem. Most speculate it is an issue with the VarioCam system. My car ran perfectly fine until I reached about 4,000 miles. Now it feels much like a misfire at the aforementioned RPM range. Have you encountered any cars with this issue? Do you believe your flash could help?

Austin Replied:
"Hello Matt,

I have been following the thread on 6speed online. Of all of the 991S models I have ever driven, I've yet to experience that. Though, I've only driven one stock (Supreme Power's PDK 991S). If this were an inherent issue that present when the vehicle was new, it is possible that software could fix it. I am not confident that the issue could be software if it arose after about 4,000 miles. That type of timing would point to there being some kind of faulty hardware somewhere that is failing after a number of miles. That said, I have yet to hear of this issue on any of the cars that we have flashed.

Regarding our software and the X51 power kit, our software is compatible with them and we have done them with good results."

The only silver lining I'm finding in this thread is at least I know it's not just me. I wanted my car to be so perfect that I was trying to ignore the stumble. I ordered my car and picked it up in Germany - it's not just any car to me. This was a dream come true. The fact that driving it is less than a stellar experience is really starting to get to me. There are days I don't want to drive it because I'll just obsess over the hesitation :(.

Also, Porsche should want to make customers like me happy. My first car was a 911. I own two right now. I'm what they consider a "customer for life". So I'm a bit disappointed in my local dealer for not pursuing a solution or at least a valid explanation. But then I have to remember that the local dealer is not Porsche. They just sell and service them. I wonder how much influence / care PCNA really has... Or are they just disconnected too much?

Hopefully we'll all stick together on this, get more people to acknowledge this issue, and eventually find a solution with or without PCNA's help.

If anyone here is delusional enough to think that PCNA will address (let alone acknowledge) this problem, then you're in for a rude awakening.

Nick Murray's situation should be a case study in Corporate arrogance. It was not until the proverbial mouse roared that they even gave him the time of day. And his was a dangerous car that was randomly dying (with video evidence).

Sadly we're on our own here. Perhaps if enough people come forward (some 981 folks are also experiencing the exact same stumble) or there's a threat of legal action, there is nothing to compel them to do anything.

The question I have is what's the point of maintaining ones warranty, if the warranty doesn't compel them to fix an obvious problem. And when you do try to fix it yourself, they claim that your fix voided the warranty.

Pure genius...

Your post is pure genius. Hit the nail on the head!

I wonder what a good Indie would charge to try and diagnose the problem with a PIWIS? Not really sure if it would be worth the effort if there are no codes popping up. It would appear that may be our only option, as the dealers and PCNA don't seem to care.

I had a much more minor issue when I bought my first new 911 back in 99', I had some issues caused by the dealer and both the dealer and PCNA took care of the problems and compensated me for my time. I guess things have changed since then.

I didn't read the entire thread but I would encourage you to reach out to the local PCNA rep and let him drive your car and then see where it goes. I wouldn't give up.

I know it won't do anything, but I'm writing a letter to PCNA headquarters pleading my case. It will at least make me feel better :).

Do you know who the local rep is? I would start there.

I do not. I will ask around in my local PCA region (Potomac) as I'm sure someone has personal contacts. I also know the General Manager at my local dealer. I think it's time to have a word with him but I've been reluctant because he'll just have my same ol' service rep contact me and then it gets ugly when he knows I had to go around him.

For now, I have written a two-page letter to PCNA headquarters. Might as well just start lobbing grenades in there, too. Don't worry, I'm starting with a well-written, nice grenade. It goes out in tomorrow's mail.

Matt, FWIW I would not go the path of software tune or a specialist aftermarket shop to diagnosis the issue. For now f:(& the dealer you bought the car from. Focus on the Ocla dealer as you can easily get there- I'll explain why below. Take the following three steps:

1). Put the stock exhaust back on and take it there during a time of day you can clearly replicate the problem with the shop Forman. Not the service guy or manager, the mechanic foreman - he typically has special certification but more importantly the regular mechanics work on billable job orders. They get paid, I sh@t you not, on a job cost system. For example - diagnosis problem a) book says get paid 3 hours to fix, if it takes them 6 hours to do - they only get paid for 3 hours, if it takes them 1 hour, they're ahead. These guys typically work 50 hours and get paid on average for 35. That's why if they don't get an error code they stop immediately because they're not getting paid until the prove a problem. Error code = job code = problem getting fixed. The shop Forman on the other hand is not paid the same way - he gets a salary and bonus, so he can invest the time to solve the problem and take on a special project.

2) if you're not successful with 1), tell him you respectfully disagree and want to bring the car back when the regional rep is there - you don't want to leave the car for the rep, you want to be there and take the rep for a drive. They'll balk at this because the rep doesn't want to deal directly with you, rather use the dealer as an interface. Tough, they're going to do it and if they push back, tell them you're going to respectfully call PCNA and request it from them directly. You shouldn't need to go there, but just in case, you'll have a contingency plan.

3) if not successful with 1 and 2, bring it back a third time, I'm sure it won't get better and then if they still can't figure it out, go get a lemon law lawyer or call the selling dealership back and see if they'll buy the car back where you're not losing more than 1k per month of ownership.

The local dealer has the same obligation to fix the car as you're purchasing dealer, so go where it's convenient and you can accomplish 1 -3 without rearranging your life- FYI I'm listed as Black Beauty on Rennlist (SilverSled was my 997) you've helped so many of us with your posts and we know you've got some big events coming up - just pace yourself here "Strategy is the craft of the warrior." Miyamoto Musashi - 16th Century Japanese Undefeated Samurai. Good luck!!!

@Silversled - All very good advice, but for one small problem - "It's operating as intended."

That has been the party line for all of us who have been to a host of different dealerships, who ALL said the same thing (mainly due to the lack of an error code).

The nonsense regarding his exhaust is more of their tried and tested stonewalling tactics.
Sure, he can take off the exhaust and take the car back in with the same complaint - now what?
Still no code to send back to Germany..

I've dealt with my technical foreman who claims that he's raised the issue.
I've also contacted PCNA and have a framed case number hanging on my wall.
I've even met with the charming PCNA rep.
I've taken the car in FIVE times only to be told yup, we feel it, they all do it and..."It's operating as intended."

And therein lies the age old problem of subjectivity..

Until there's a TSB (such as http://www.automd.com/tsb/bulletin_b360152/ ) they won't be in any great rush to do a thing.

I have ZERO faith in Porsche and their desire to do anything other than sell cars.
And I certainly don't blame the dealerships who are operating within the confines of their well defined (German) sandbox.