Engine Stumble on Roll Out
09-14-2015, 09:53 PM
#152
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Engine "stumble"
I had my 991 C4S engine hesitation / stumbling for quite some time until it was so bad I ended up at the dealership and "stumbled" upon a 991 GT3..... end of story (for me).
01-03-2016, 02:15 PM
#153
Wow!
I never followed back up with this thread I started long ago! I was logging back on to check things out one more time as I'm about to turn in my lease.
This problem was never solved for me. In fact, I've once had the car completely die as I attempted to pull out of a turn around under an overpass. Car acted like not enough throttle was applied for the given clutch position. Reminded me of when I was learning to drive a stick 16 years ago! I've also had the car refuse to shift out of second gear. It'll rev up and the PDK will start slipping at the gear change until some throttle is removed and reapplied. Both of these issues are too random to prove to Porsche so nothing was ever fixed.
I'm convinced it's a software issue. The car when completely flogged upon drives great, but when you just have it in sport and want a quick burst of speed, you're ****ed. The car loves to jump into 2nd gear, which is worthless below about 55 mph. To get it to stay in 1st, you need like 75% throttle, which is often too much for the situation. It's really very binary on the launch, not linear at all. The car is programmed for efficiency. Sport is just not aggressive enough. It still waits for you to give a period of high throttle and steering (i.e. pull some gs) before it realizes you actually want to drive it. Sport+ is too aggressive for the street. I've seen some verbiage on the 2016s that Sport mode puts the car in maximum throttle response. Around a track or generally driving like a maniac the car is fine, but I can't drive on the street like that. I occasionally need all the power the car can apply and I need it now. Car is just too unpredictable in power delivery on the street.
I drove my car for nearly two years now as a daily driver. I have about 22k miles on it. It was my first Porsche and will be my last. I don't do enough tracking for it to be worth it the premium Porsche charges over other German performance coupes and sedans.
I never followed back up with this thread I started long ago! I was logging back on to check things out one more time as I'm about to turn in my lease.
This problem was never solved for me. In fact, I've once had the car completely die as I attempted to pull out of a turn around under an overpass. Car acted like not enough throttle was applied for the given clutch position. Reminded me of when I was learning to drive a stick 16 years ago! I've also had the car refuse to shift out of second gear. It'll rev up and the PDK will start slipping at the gear change until some throttle is removed and reapplied. Both of these issues are too random to prove to Porsche so nothing was ever fixed.
I'm convinced it's a software issue. The car when completely flogged upon drives great, but when you just have it in sport and want a quick burst of speed, you're ****ed. The car loves to jump into 2nd gear, which is worthless below about 55 mph. To get it to stay in 1st, you need like 75% throttle, which is often too much for the situation. It's really very binary on the launch, not linear at all. The car is programmed for efficiency. Sport is just not aggressive enough. It still waits for you to give a period of high throttle and steering (i.e. pull some gs) before it realizes you actually want to drive it. Sport+ is too aggressive for the street. I've seen some verbiage on the 2016s that Sport mode puts the car in maximum throttle response. Around a track or generally driving like a maniac the car is fine, but I can't drive on the street like that. I occasionally need all the power the car can apply and I need it now. Car is just too unpredictable in power delivery on the street.
I drove my car for nearly two years now as a daily driver. I have about 22k miles on it. It was my first Porsche and will be my last. I don't do enough tracking for it to be worth it the premium Porsche charges over other German performance coupes and sedans.
Last edited by Magnus357; 01-03-2016 at 03:28 PM.
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lunarx (09-18-2019)
01-03-2016, 02:43 PM
#154
No stumbles here, in the 1800 miles I've driven it, in the past couple of weeks. I paid close attention to it, after reading this thread. I'll have my SA make a note to not "upgrade" my ECM, ever!
01-03-2016, 03:52 PM
#155
I've had the 2.5-3k stumble fixed by the dealership, but I've also had the occasional roll-out stumble like you guys describe and have learned to replicate it or avoid it.
If I move my foot quickly from the brake to the throttle at a light, the car dumps the clutch, and if I don't continue immediately with more throttle (i.e. I move my foot quickly to a given throttle position and then leave it there), it bogs down and at that point, even if I add a bunch more gas to correct, it takes it a bit for the car to recover.
There are three ways to start off that never seem to stumble:
1. Just let off the brake and let the computer figure out the start without any throttle at all until the clutch is fully engaged.
2. Progressively increasing the throttle, so my foot never stops at a certain position.
3. Adding a lot of throttle immediately.
After the start, I never have issues with the car selecting the wrong gear because I only drive the PDK in manual mode unless I'm doing a launch control start.
It doesn't really feel strange to me to have to learn to adjust your throttle inputs to get a DCT to do what you want it to, after all you wouldn't find it strange on a traditional manual.
If I move my foot quickly from the brake to the throttle at a light, the car dumps the clutch, and if I don't continue immediately with more throttle (i.e. I move my foot quickly to a given throttle position and then leave it there), it bogs down and at that point, even if I add a bunch more gas to correct, it takes it a bit for the car to recover.
There are three ways to start off that never seem to stumble:
1. Just let off the brake and let the computer figure out the start without any throttle at all until the clutch is fully engaged.
2. Progressively increasing the throttle, so my foot never stops at a certain position.
3. Adding a lot of throttle immediately.
After the start, I never have issues with the car selecting the wrong gear because I only drive the PDK in manual mode unless I'm doing a launch control start.
It doesn't really feel strange to me to have to learn to adjust your throttle inputs to get a DCT to do what you want it to, after all you wouldn't find it strange on a traditional manual.
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lunarx (09-18-2019)
09-18-2019, 01:01 PM
#156
Wow!
I never followed back up with this thread I started long ago! I was logging back on to check things out one more time as I'm about to turn in my lease.
This problem was never solved for me. In fact, I've once had the car completely die as I attempted to pull out of a turn around under an overpass. Car acted like not enough throttle was applied for the given clutch position. Reminded me of when I was learning to drive a stick 16 years ago! I've also had the car refuse to shift out of second gear. It'll rev up and the PDK will start slipping at the gear change until some throttle is removed and reapplied. Both of these issues are too random to prove to Porsche so nothing was ever fixed.
I'm convinced it's a software issue. The car when completely flogged upon drives great, but when you just have it in sport and want a quick burst of speed, you're ****ed. The car loves to jump into 2nd gear, which is worthless below about 55 mph. To get it to stay in 1st, you need like 75% throttle, which is often too much for the situation. It's really very binary on the launch, not linear at all. The car is programmed for efficiency. Sport is just not aggressive enough. It still waits for you to give a period of high throttle and steering (i.e. pull some gs) before it realizes you actually want to drive it. Sport+ is too aggressive for the street. I've seen some verbiage on the 2016s that Sport mode puts the car in maximum throttle response. Around a track or generally driving like a maniac the car is fine, but I can't drive on the street like that. I occasionally need all the power the car can apply and I need it now. Car is just too unpredictable in power delivery on the street.
I drove my car for nearly two years now as a daily driver. I have about 22k miles on it. It was my first Porsche and will be my last. I don't do enough tracking for it to be worth it the premium Porsche charges over other German performance coupes and sedans.
I never followed back up with this thread I started long ago! I was logging back on to check things out one more time as I'm about to turn in my lease.
This problem was never solved for me. In fact, I've once had the car completely die as I attempted to pull out of a turn around under an overpass. Car acted like not enough throttle was applied for the given clutch position. Reminded me of when I was learning to drive a stick 16 years ago! I've also had the car refuse to shift out of second gear. It'll rev up and the PDK will start slipping at the gear change until some throttle is removed and reapplied. Both of these issues are too random to prove to Porsche so nothing was ever fixed.
I'm convinced it's a software issue. The car when completely flogged upon drives great, but when you just have it in sport and want a quick burst of speed, you're ****ed. The car loves to jump into 2nd gear, which is worthless below about 55 mph. To get it to stay in 1st, you need like 75% throttle, which is often too much for the situation. It's really very binary on the launch, not linear at all. The car is programmed for efficiency. Sport is just not aggressive enough. It still waits for you to give a period of high throttle and steering (i.e. pull some gs) before it realizes you actually want to drive it. Sport+ is too aggressive for the street. I've seen some verbiage on the 2016s that Sport mode puts the car in maximum throttle response. Around a track or generally driving like a maniac the car is fine, but I can't drive on the street like that. I occasionally need all the power the car can apply and I need it now. Car is just too unpredictable in power delivery on the street.
I drove my car for nearly two years now as a daily driver. I have about 22k miles on it. It was my first Porsche and will be my last. I don't do enough tracking for it to be worth it the premium Porsche charges over other German performance coupes and sedans.
Funny story...
I bought the OP's car as a CPO from Porsche North Houston. I had it from Feb 2016 to Sept 2019. I added another 27,000 miles on it. I ended up selling it to Carmax last weekend.
I had the same issue OP described multiple times during my ownership and I took it in to have the dealer look at it. Nothing ever came of it. It was very annoying and I basically adapted to driving the car a certain way to compensate for a potential stumble. It wasn't what I expected for a 100K car. Definitely left a sour taste in my mouth. I wanted to keep the "last of the NA 3.8 engine" but eh...
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lunarx (09-18-2019)
