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.