......problem! I recently have been getting a cel code. When I checked it, it said system too lean. I replaced the fuel filter and it fixed the problem. Car has been running fine untill today. I got another cel code and it was code 131 #1 o2 sensor circuit voltage too low. Checked readings with my scanner and the voltage is at 0 and dosn't move. Would this mean its bad? Or could it be something else again? Also the exhaust smells rich.

 

sounds like the sensor is bad. they should be replaced every once in awhile, even if they arent throwing codes. so its not a bad replacement to do anyway. but it should clear that up.