Edgy01

Is anyone else hearing the common sound of engine knocking (at least starting to) when you accelerate with the typical fuel we find in California (91 octane)? I hear it and then it goes away,--like the Vario-Valve is detuning actively to adjust. Maybe I'm not describing it well, but it sure sounds like that engine knock sound I used to hear years ago. Obviously, it doesn't last long,--maybe a second or so.

micgreeny

yes, I know what your talking about. mine has done that from day one.

ChrisF

mine did it when I first bought it, but I immediately put in a tank of Unocal 91 one and no sounds since.

gweedo911

mine has been doing it for a while....

CharlieJr

Is this different than the dreaded "hesitation" problem??

ChipAZ

I avoid getting gas in Calf. at all costs.

cmoss

easy to do in tucson

avdiscolo

I just started noticing this in my '06 C2S after major engine work (replaced head gasket). The knocking appears very infrequently. In fact, for me it seems that it happens between shifts and *not* under load. I have not been able to reproduce this under load at any time.

I always use 92 octane gas from either Chevron or 76 here in WA.

diverdan

No problems on Chevron 92 octane.
I do have some rattling when the car is first started cold in the morning, but that goes away after idling about 5 seconds.

rcg412

they replace head gaskets in 996/997s... thought it was an engine replacement?

Stephenkng

Where can you get Chevron 92 in Bay area???

cvazquez

Try adding half a bottle of octane booster to a full tank of gas or change your gasoline station.

diverdan

I usually get mine at the Chevron at Peninsula and Delware in San Mateo.

Stephenkng

Thanks. I may want to try that since I work in So. San Francisco.

dasams

As suggested by another poster, please add octane booster and let us know whether the sound goes away. If confirmed, this suggests to me that CA cars should get ECU updates to detune to 91 octane. After all, you aren't doing your engine any favors even if the knocking is very brief.

Such a shame...