Vancouver83LTD

We filled up at a love's (no gas for miles, needed to fill up)
water in the gas, it had been a very wet night and the car was acting up - so we got ethyl alcohol to mix with the water and it took care of the problem (for that tank anyways)

Bullet

I had the EXACT problem yesterday with 9,600 km on my '06 C2S on a cold day at -0.5 degrees Celsius while using 94 octane gas with up to 10% ethanol from 'Husky' - a Canadian gas supplier.

I must say that I find the gas theory very sketchy.

Anyways, I haven't run my car since, but I will tomorrow to see if the problem persists.

Has anyone gotten to the bottom of this yet?

Coochas

I just dropped the kids in the pool.

Jon Elliott

Washington has 92 max

icruze

Others have experienced the same thing.

https://rennlist.com/forums/997-forum/277930-my-car-acted-up-big-time-hesitating-and-very-jerky.html

I believe there are other threads as well if you search under engine hesitation. Doesn't seem to have a known cause and goes away for most.

Edgy01

We've seen this before with several Carrera owners. I have experienced it once myself. I have about 10,000 miles on my 06 S. It doesn't appear to be fuel related nor temperature related (ambient). In fact, we're not really seeing any common variables so far. One owner has had his car rigged with a PCNA-supplied black box with instructions to press a button when he experiences this again. There are myriad theories on this from fuel, to atmospheric pressure, to fuel level to a sticking fuel plate.

MMD

It's sometimes like glitches/corruptions in computer software. The average user has no idea of what's wrong, has no idea how to fix it, but just wants it fixed. If "check engine" light goes on, take to dealer; if CE goes on _flashing_ do not drive and get it flat-bedded to dealer; otherwise just take to dealer.

bdmason

if you had a choice of 93 octane gas which brand would you use? I use mobil and I have a choice of about 4 others

Tony356993

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Update-

The car ran rough for 2+ days and about 45 miles. I filled up the tank, tried the gas cap trick. tried the oil cap trick and plugged in my cheapo code reader (no faults).

I took it to the dealer today (about 20 miles) and the car ran perfectly! Since I already had the appt, I let them check the car. They ran some code reports and said they would send them to Atlanta to see if there was anything that they could do.

The tech aksed me if i , by chance, had put the key in the car and turned the key but did NOT start the car. I said that I did since I was trying to read any fault codes. He said that if you put the key in and turn the key w/o starting the car, it kind of resets the electronically controlled throttle.

I do not know if that "corrected" my symptoms but I though I would post the data.
__________________

Bullet

So it seems as though nobody has any real clue what causes this.

I thought I'd just ad that it started as I was climbing a big hill with a significant elevation change. In fact, my ears usually pop once or twice climbing this hill. Maybe that alters the air/fuel ratio or something . . . I dunno since I'm not that technically inclined. I already live at a significant elevation of about 3500 feet.

It really sucks to drive a Porsche 911 and have these sort of problems and no clue what the cause is. The unpredictability and lack of knowledge and control over it are unnerving. While I realize that any and all complex man made products are prone to glitches, at this price point, it is particularly frustrating. I'm not driving a Yugo.

etmorcus

My car had the same problem here on the West Coast many times. I finally got the Regional Porsche Service and Sales reps out. It was diagnosed as resetting the throttle plate having to do with drive by wire. It hasn't returned since. Previously, it was in the shop every two weeks for the same problem for th first two months of ownership. It certainly was scary as he dbl toothpicks.
If the dealer can't diagnose it, insist on Porsche coming out. It is dangerous not being able to accelerate.

Good luck,
E

Bullet

That is interesting - the hesitation was caused by oscillations of +/- 2-300 rpm. I wonder if this would represent the different engine speeds for any given position on the accelerator in normal vs sport mode. Perhaps it is a computer glitch causing it to switch between those 2 throttle maps? I also wonder if it could be an issue with the Varioram. On my 996, I could detect the change in the Varioram around 3200 rpm with a noticeable little kick in power and RPM that reminds me of the engine speed oscillations I experienced, though the Varioram effect on the 996 was much more subtle (and not even perceptible on my 997).

The other common feature to this problem is that is seems to only be an issue while the throttle is open. With foot off the gas, as the rpm wind down, it was smooth . . . in my opinion, that points away from a problem with the gas quality, and is consistent with a computer glitch.

(the other thing about the gas quality issue is that I didn't have any such problems when using up the first 2/3 of the gas in the tank, so why then?)

Bullet

Well it's consistently still doing it today, even after filling up with fresh gas. It hesitates and jerks and the rpm oscillate in normal, sport, and PSM off modes. The problem persists even after some"spirited" driving, and all diagnostic lights on the dash remain off. I also noticed that it does it both during acceleration and with the accelerator all the way out while winding down, though it's less noticeable. It does it throughout the rpm range, though its most noticeable between 3 and 5000 rpm, probably because the torque curve is steepest there.

I guess I'll bring her in next week . . .

Tony356993

did you try to turn the key w/o starting the car and let it sit for about 2 minutes? i was told this resets the computer. can't hurt.

500

Bring it to the dealer tody while the car is still doing it as this can be a bitch to diagnose without codes and without symptoms!