Engine Performance problem
2000 Jeep Cherokee 6 cyl Four Wheel Drive Automatic 149000 miles
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My check engine light has been off and on for around six months, but the engine ran fine. My engine is now running and idling so rough, it feels like it will cut off. The code is P0302 which is a cylinder misfire. When I am idling or in reverse, the rattling seems to get worse. I have replaced the spark plugs, coil pack, had the fuel injectors cleaned, new fuel filter, new catalytic converter, but nothing seems to be working to fix the problem. The mechanic who worked on it said he believes a valve is burned. I am not even sure what to do next.