I have a 2000 Toyota 4runner with ~125k miles, and out of nowhere my gas milage dropped from 18/19mpg city to 9-10mpg. I took my 4runner to the dealer, who ran the diagnostic test and drove it around, and said they could not find anything wrong with it and the test did not display any codes. My tire pressure is fine, I replaced the air filter a month or so ago, and the oil was changed ~3k miles ago. The only thing different that I notice is the brakes now squeak when I apply light to medium pressure on the brake pedal.

Any suggestions?

Stuck caliper? feel the wheels for heat.

Is it pulling to one side or t'other?

just installed some heavy rims?