My Engine light has been on for a while, but I've been ignoring it . I just check it tonight using the paper clip method and my ECU read trouble codes 71, 72 and 74. I looked it up and it is cylinder misfires. . What do I do?!? My car sounds like it has a cold. It coughs sometimes. I have NGK iridium spark plugs and wires. I didn't gap the plugs b/c the instructions said not to. What could be the problem? Some good technical advice would be greatly appreciated.