2003 Mitsubishi Eclipse GTS OBD2 Codes P0150, P0154, P0155, P0156, P0161 and P0303 - O2 Sensor & Cylinder 3 Misfire Diagnosis
My 2003 Mitsubishi Eclipse GTS (112,000 miles) is showing multiple OBD2 fault codes: P0150, P0154, P0155, P0156, P0161, and a cylinder 3 misfire code (P0303). The vehicle has been running smoothly until recently, with no noticeable performance issues. The only symptom I've observed is slightly rich fuel mixture. Given the age of the car and the presence of multiple oxygen sensor-related codes, I'm concerned about potential sensor failures or injector problems. I'm looking for advice on diagnosing and resolving these codes to restore proper engine operation.
Addressing the P0303 misfire is likely to clear the oxygen sensor codes. A common cause could be a faulty fuel injector in cylinder #3. This is a reasonable starting point for diagnosis and repair.