Took my car to the dealership because I have a strange misfire occuring at around 40mph in 4th gear. It isn't terribly bad but enough to be incredibly annoying in city driving. Dealership concluded that there is a slight misfire... this problem has been occurring for a while now and no cure. Replaced my plugs, wires, and coil pack. It seems worse when I am coasting. no engine trouble code is present which is why the dealership could not help. Anyone have any idea?