A 2000 Rodeo would have Multiport EFI regardless of powerplant. Fender badges at the Cardomain website would indicate this one has a V6 (3.2?).

O2 sensor(s), Engine Coolant Temp sensor, thermostat, leaking injectors, plugged cat/muffler, problems with MAF sensor, slightly misfiring spark plugs, dirty air filter, even dragging brakes, could cause poor mpg.

BTW was the speedo recalibrated for the larger tires? That'll drop it down some no matter how well the engine's running. You could just check mile-markers for 10 miles or so on the hiway to see how slow the odometer is running and calculate mpg accordingly.

Probably need to plug into an OBD-II diagnostic computer and see if there's anything abnormal.


HTH...........ed