I replaced a bad wheel bearing and did a wheel alignment. My 97 Legacy was averaging 24 mixed and 26 highway. Last month, I started hearing a loud rumbling in the rear that I thought was the muffler/tailpipe. I had the tailpipe replaced a few months ago and thought going thru snow maybe loosened the pipe, which caused the noise.

 

When I bought it into the shop, it ended up being a bad rear wheel bearing. After replacing the bearing, and getting a wheel alignment done, my mileage went up to 28 mixed and 31+ highway.

 

I'm pretty psyched... I guess the friction of the bad bearing and bad alignment was eating up all of my gas.

Probably the alignment. Losing 4 mpg as heat in a bad bearing probably wouldn't last very long. Congratulations.

You probably saved a set of tires with the alignment too.