HouseCallAuto 2/3/2013Replace the spark plugs and / or ignition wires for cylinder 3 & 4 with the plugs and wires from another two cylinders that are not misfiring. ISee if the misfire either goes away or moves to the other two cylinders to test the integrity of the wires and plugs. If the miss moves, replace the wires and plugs. if the misfire remains at 3 & 4, then switch the ignition coils from 3 & 4 with two other cylinders' coils. See if the miss moves and replace coils as needed.