Some modern cars have a individual coil on each plug.
When you get a misfire code, it could be worn plug or a coil going bad.
Smart move is to change the plugs first(actaully smartest move is to do a preventative mainetenance practice of changing plugs at regular intervals, say 25K miles like I do on my 4.7 Jeep) and if the code does not go away, you can swap the coils between two cylinders and see if the code follows the swapped coil. If it does then that is the problem.
The other problem I have been told is some folks get a lot of crud built up in the combustion chambers and back of the valves on the 4.7 which can give a misfire. I was at the local store talking to a pal who is a tech. Was working on a 06 Jeep with a 3.7 v6(same as the 4.7 with 2 less cylinders) and only 40K miles.
Had a tick, sounded like a very bad lifter. He told me he has scene 4.7 and 3.7's spit rockers out because of build up, generally due to runnung cheap gas and around town driving. So he did an injecotr service on it. They unhook the fuel rail connection and have this canister with FI Cleaner solution and hook it up to the rail and use compressed air to for it in and start it up, The engine runs off this solution for about 10 minutes as I recall. then they hook the fuel supply back up and take it for a ride. It cleans out all the [censored]. The engine was nice and quiet after he did the service, I couldnt believe it. I try to run Techron a couple times a year as a prevetntive but now wouldnt hesitate to have that service done if needed after witnessing that, I used to think they were a
waste but guess not.
When you get a misfire code, it could be worn plug or a coil going bad.
Smart move is to change the plugs first(actaully smartest move is to do a preventative mainetenance practice of changing plugs at regular intervals, say 25K miles like I do on my 4.7 Jeep) and if the code does not go away, you can swap the coils between two cylinders and see if the code follows the swapped coil. If it does then that is the problem.
The other problem I have been told is some folks get a lot of crud built up in the combustion chambers and back of the valves on the 4.7 which can give a misfire. I was at the local store talking to a pal who is a tech. Was working on a 06 Jeep with a 3.7 v6(same as the 4.7 with 2 less cylinders) and only 40K miles.
Had a tick, sounded like a very bad lifter. He told me he has scene 4.7 and 3.7's spit rockers out because of build up, generally due to runnung cheap gas and around town driving. So he did an injecotr service on it. They unhook the fuel rail connection and have this canister with FI Cleaner solution and hook it up to the rail and use compressed air to for it in and start it up, The engine runs off this solution for about 10 minutes as I recall. then they hook the fuel supply back up and take it for a ride. It cleans out all the [censored]. The engine was nice and quiet after he did the service, I couldnt believe it. I try to run Techron a couple times a year as a prevetntive but now wouldnt hesitate to have that service done if needed after witnessing that, I used to think they were a
waste but guess not.
