[mikeyac]

2006 4Runner V8, 210,000
Within one tank of gas the MPG has gone from 18MPG to 14.5 MPG. Two independent Toyota garage and Toyota dealerships can't find anything wrong with the auto. I have done a tune up with new spark plugs, air filter, cleaned fuel injectors, etc. There was a sudden change that no can figure out.

 

[fourwd1]

Maybe a leak, do you smell gas?

 

[Zembonez]

Transmission is starting to slip?

Clutch packs do wear (especially at your mileage) and start to slip. Much like a clutch failing in a manual, this can happen rather quickly. Torque converter can fail as well.

Caliper sticking?

Rear brake shoe dragging?

 

[SUPRG]

Fuel filter or cata converter, would be my guess. I have had a caliper freeze on the front rotor, but I smelled and could feel the heat immediately. Did you gas up at a warehouse store? My boss claims his MPG dropped significantly when he bought cheap gas at C*****.