anyone know how to check the oxygen sensors on a 3.0 4runner? is that even possible without a scanner?

 

dont think theres anyway with out knowing what codes its throwing

 

Check your FSM. You can test it under operation. Basically you get the engine warm, then make sure that the 02 sensor is "dithering" - moving from about .25v to .75v under normal conditions at abou 1400 rpm or so...

 

Unplug the sensor (probably under the driver's seat). Resistance between the two terminals away from the mounting plug should be between 5.1 & 6.3 ohms @ 68degF. Post your results - if you need more info, I can post it, but it'll be long.