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?

 

 

My 3rd gen pickup has a siphon screen and a locking fuel door...factory.

 

And you also have 1 bolt that would let someone drain all of the gas in under a few mins.

 

real talk... lol if someone wants your gas, and knows how to get it. expect to be empty in minutes.

 

4 bolts to pull the skid plate to get to the drain plug, but yes it has a drain plug. And you'd have to know it was there.

 

plugged fuel filter? my only guess

 

Now that's just silly! A plugged fuel filter can only increase MPG!! As less gas is getting to the engine to burn.

 

Bad O2 sensor
Plugged cat or muffler
dragging brakes