Originally Posted by 1StopJeff

Cheaper gas, i.e. Costco, Arco, tends to have higher sulfur levels than top tier fuel. I purchased a Corvette a couple of years ago and the fuel level sensor stopped working and the CEL came on a couple of months after I purchased it. After some research I found that it was due to cheap gas and sulfur build up on a sensor in the tank. Filled the car with Chevron with Techron and added a bottle of the additive, reset the CEL, stuck to top tier fuel and never had the issue again.

Originally Posted by SoCal C2S

On my previous cars I took the Costco gamble about a dozen times and was bitten twice with bad fuel. Bad fuel meaning the octane advertised was not delivered....verified by analysis (second occurance). After that I stayed away and stuck to top tier fuel.

Fuel should have been 91 octane but ended up being 88 by analysis (just the second batch). Not sure if they had regular in the premium tank or what....FWIW, it took six months for Costco to respond to my claim and three additional months to refund my purchase.

Originally Posted by rickdogg82

Costco's gasoline is Top Tier although might not have been when you had your problems.

Originally Posted by SoCal C2S

Short trips are not desirable for reasons stated above...it is worse for the 997.2 because of the direct FI. Trips where the engine doesn't reach full operating temperature is conducive to aide in carbon buildup on the intake valves (seats). I have had two DFI engine cars that were plagued by this for the same reason, short trips.

Get out and drive! That's what Porsche means in any language.