i have a 2005 gtp comp g with about 32000 mi and it has a missfire in neutral that shakes the car plugs have been changed the dealer took a look at it and said now this is funny to me "theres a missfire code but nothing is wrong with it you will have to wait till it completely breaks down before we can do anything" sounds to me they have a very bad diagnostic force and can only replace things that are obvious anybody have any comments on the missfire like some things to check sorry for the long post