I have a 2003 2500 HD 4WD with 6.0 Gas V8. The check engine light periodically will begin blinking. It can blink for 2 minutes or for an hour, then it may quit for days. It has been doing this for months. My mechanic put it on the analyzer and got a Code 300. He said it is a misfire but he cannot pinpoint where. He suggested changing wires, plugs, coil packs, etc. Before I start replacing parts, does anyone have any thoughts? I've read where people say you should stop driving the truck immediately but, like I said, it has been doing this for a while and I have no problems in performance or gas mileage.