When it rains it pours. I've been driving my 6 maybe 2 days a week for the past few months and it seems that lately since the bitter cold began when I start it up something new develops. About a mile after filling up with Amoco 93 last night, the engine started sounding like it was missing on some cylinders. Revs fine in neutral but has about 50% power otherwise. Bentley says bad gas could be the cause - yeah right!