I have a 06 997 cabriolet, 6-speed ... the other night the car was bucking slightly under load, and seemed lethargic. Idles well, revs strongly when not in gear.

Coincidentally, or not, the car was pretty low on gas (30 miles range) and exhibited the problem on the way to the gas station to fuel it up. However, the problem continued after the tank was full.

The check engine light did not come on, so I assume it didn't throw any codes. Ideas?

 

High pressure fuel pump?

 

I would say spark plugs

 

This happened to me when my car was < 1 year old; a reflash of the ECU at the dealer solved the problem permanently. It idled perfectly and was fine under more than half throttle but, at part load, it would have something like a surge and bucking. That reflash solved it. By the way, I am not the only person who's had this happen and I read about this solution I believe on PCA's website or in Renntech.org... don't remember now. I hope this helps.

 

I had a similar issue twice in two years and it was cured but shutting the car off, taking off the gas cap then putting back on and tightening fully.

 

I had a similar issue right after buying my '06 C2S CPO. Once I shut the car off and let the ECU reset, it was fine for several thousand more miles until the fuel pump ultimately went. It didn't throw a check engine light until when the pump died at a gas station and the car wouldn't start. Yours may be on its way out.

 

Thanks for the head's up, appreciate it. Glad I sprung for the aftermarket warranty.

 

Had a similar issue when below a quarter tank on two occasions. Fill up and a few moes driving cured the problem.

 

Not in an 06.

 

when it is doing this, do the RPMs climb and fall around? If so you may want to look at a slipping clutch as a possible culprit

 

Car was back to its normal self on the way to the dealership this morning for a suspension issue. Never threw any codes. Strange.

 

Mine didn't throw any codes either. Neither did it have to do with the fuel level or how tightly the gas cap was closed. In the end, I requested a reflash of the ECU, as I read on either PCA's or renntech.org's websites and the issue was permanently solved.