I have a 2004 Mitsubishi Endeavor, I cannot get around the check engine light. I took it to Advance Auto and replaced an O2 sensor from the lower front bank, however the light came back on after about 30 miles. I returned to Advance Auto now they suggest it maybe the rear lower bank. Has anyone else had this occur and if so how did you resolve it?

I am also told it could my catalytic converter, Mitsubishi wants $1200.00 to replace it.

Help!!!!

 

Its you cat converter. O2 sensors never set those codes.

 

why do people NOT have their problems diagnosed by people that know what they're talking about? (and im NOT talking about the morons at autozone).
take the car to the dealer and get it diagnosed/repaired correctly.