1999 Montero Sport Check Engine Light: Codes P0141 and P0307 - What to Do?
Hello everyone, I'm new to this forum. The check engine light has come on for the second time on my 1999 Mitsubishi Montero Sport. Initially, I received code P0304, indicating a misfire in cylinder 4. A sales technician recommended an engine cleaner to clean the fuel injectors. After adding the cleaner to my gas tank, the issue temporarily resolved. However, about a month later, the check engine light returned, and this time I've been diagnosed with both codes P0141 and P0304. My current plan is to replace the spark plugs and ignition wires. Are there any additional steps or diagnostics that could help resolve these issues—particularly for code P0141 (oxygen sensor heater circuit malfunction) and P0304 (cylinder 4 misfire)?
I recommend replacing the spark plugs, ignition wires, distributor cap, and rotor. These components are common causes of cylinder misfires and can significantly improve performance and eliminate P0304. For P0141, ensure the oxygen sensor heater circuit is properly connected and not damaged—check for loose wiring or corrosion at the sensor connector.