OK here's the background have a 1999 Yukon with 350 Vortec 4wd and was getting a P0303 code (#3 cylinder misfire). So here is what has been done Cats, Fuel Pump, MAF, Cap, Rotor, Wires, Plugs 14 months ago, Crank Sensor, Air Filter 6 months ago, Intake Gaskets, #3 Fuel Injector, Plugs, Coil, set...