ok i had my check engine light coem on my 91 22re pickup, code 21 which is bad 02 sensor. Before i go replace it, is there anything that can give me a false reading?

 

Is your truck getting lousy gas mileage?

 

I have that stupid code go off all the time in my truck... I've replaced the O2 sensor 4 times in 1 year.... GRRRRRR. Desert let me know what you find out if anything.... I've heard that you should only get a dealer O2 sensor for it, which may hold true, since my truck has eaten an OReilly's, an Autozone, and two Advance Auto Parts O2 sensors. That or my truck is hungry for O2 sensors (which means I got another problem). And MPG wise, I'm getting usually around 13, which is way not right.