I own a 2001 RX300 and am now getting ready to replace the second oxygen sensor in less than six months. They are pretty expensive $300+. I have been guilty of using regular gasoline on occasion in this car and have been told by my mechanic that using regular gas may have destroyed the sensors.
Has anyone else had a problem like this?

 

Regular gas should not hurt the O2 sensors, it will make the engine ping, but should not hurt the sensor. Do you use and fuel additives? Also has any work been done on the intake? Some gasket dressings are not compatible with O2 sensors, and can damage them. Also, how many miles is on the car? O2 sensors do wear out. Lastly, $300 is high for 1 sensor, did you take it to a dealer?

 

No - I didn't take it to the dealer but to a mechanic that strictly does work in imports and has been in business for 23 years. He has been very reasonable on other things. I have 76,500 miles on the car. The $300 does include the labor but at your suggestion, maybe I should shop it. He told me there are three o2 sensors. Since the car is 8 years old, maybe they just wore out. Thank you very much for your input. I don't know if any work has been done on the intake. I did the 60,000 mile maintenance awhile back.

 

$300 is on the high side, but if you trust them otherwise. Do you know which sensor they replaced last time? I just got done replacing both the sensors in my es300, and there is a big difference between the front and rear.