Re: 87 Octane Fuel
I am cheap...although I prefer the term frugal...and have used midrange (89 octane) in my Audis and Crossfires since I bought them. That's 116k miles on the A6 and a total of 40k between the two 2005s. I have been blending 89 and 91 in the Crossfires, but since I am driving them so seldom and after reading these posts, I will stick with only premium from now on. As far as the A6, it is a lower compression engine than the 3.0 and 4.2 engines and at 153k miles, I think it is now used to midrange and if I was going to have a damaged engine, it would have happened by now. If it happens at 160k or 180k or 200k, who's to say it was the gas vs old age?