Patrick D 483

E85 is ethanol fuel instead of just gasoline. See if your car is setup to run on it first.

It sounds like my Yukon's rear end is going Vooooom, pause half a sec, voooom at around 75 or higher. My BF Goodrich AT tires have about 30k miles. It could be them but them have been very quiet up to this point. Anyone else faced this?

My 17 Yukon also has recently started a humming noise at around 75 mph. I have about 30k miles on my BF Goodrich AT tires so I am thinking that could be it but I rotated tires recently and it didn't change. Sounds like rear axle but it sounds like Vooooom, half second pause, Voooom. I am about to go to shop again tomorrow, not a dealer, and I described it to them before when they replaces a front boot or something on CV joints that did nothing to the noise.