Motor has the AFM system. Has a misfire on cylinder #7. Have replaced the lifters, coil, inj, plug and plug wire. Engine goes in and out of V4 mode with no problem and passes all wiring tests when it does so. The misfire only happens at lower speeds and seems to happen more after making a left hand turn. Not sure that has any relevance or not. Once the misfire starts it will continue even after stopping and putting it into park. If I rev the engine up to 3500RPM the misfire will stop until either I let the RPM drop below 3500 or I cycle the key. After cycling the key it will run good anywhere from a few minutes to a few days then act up again. The spark plugs center electrode was very worn compared to the other plugs but did not have a lot of carbon buildup or oil sludge on it. It was wet and had the smell of fuel. I air blew the cylinder out and did have fuel blow out of plug hole. This led me to think I had a bad coil so I swapped it out but it did not change anything. I then thought maybe the ECM is dropping the signal to that coil but why would hitting 3500RPM then start the ECM to work right and then stop working again after dropping below 3500RPM. I have had this problem before with weak valve springs but it wasn't just one cylinder and it happened all the time. With the head off the top of all pistons looked the same. It does not burn oil nor do you see any blue smoke etc. I am a retired Chrysler Mechanic and have never run into such a problem. Any advice from you all would be great. Dave
have the same problem?
Thursday, May 21st, 2015 AT 1:47 PM