My 2004 Dodge Durango SLT 4.7 V8 has a random misfire. It originally came up as a cylinder 5 misfire so I replaced the coil and did all 8 spark plugs. It went away and came back as a random misfire a day or two later when I was entering the highway. It is now just a 300 random misfire code. When I accelerate over 3000 RPMs the check engine light flashes about 6-7 times. It is definitely misfiring and running rough. There are times it barely accelerates. Any help on what could be causing this? I am not sure where to start and money is an issue so I want to try and fix it in a good order.

 

What spark plugs did you use?

 

RC12MCC4 Champion Copper.

 

Can anybody help me with this? I am looking at trying to fix this problem in the correct order. Meaning I don't want to throw money at something I don't have to. I am not sure where to start and unfortunately I don't know a mechanic that I fully trust.

 

My wifes 06 did the same exact thing. She was told by the dealership that the 4.7 motors are known for excessive carbon buildup. Its not actually misfiring but because the valves cant fully close because of all the buildup, its thinking it is. They did a chamber cleaner three times, before replacing her motor with a remanned one. They tried sea foam cleaners on hers. As i said, this was told to us.. that these motors are known for this. First time going through this. I hope i could help you somewhat with an answer.