Code P0133

[scott01ranger]

My 2001 Ranger with 160K miles will throw a CEL every few days. The code is P0133 - upstream oxygen sensor circuit slow response. The truck runs fine, although occasionally I have slight flat spot on tip in throttle response.

I assume I need a new pre cat O2 sensor?

 

[adsm08]

Yes. A P0133 is caused because the sensor's signal doesn't switch back and forth fast enough. The most common causes are a lazy heater or a worn piezo crystal, both of which are part of the sensor.