[dbartromsut]

Yep, my 08 does the same thing! It doesn't really sound like it is coming from the engine, so I don't see how running low octane fuel would make it do that. To me it sounds like its coming from the rear end... But mine does it and I do run 87 octane, so maybe. I'll try premium for a while and see what happens! You guys get way better mileage than me! I am lucky to get 10.5 mpg on the highway, but I would imagine that my tires, wheels and lead foot have to do with that!