I have a 2003 GMC 2500HD 6.6L with 130,000 miles. My problem is that it will hard start or not start at all when the motor is warmed up to normal operating temp. I have to wait till the motor cools down to start it. Yet the trucks runs great. I took it to two GMC dealerships and they dont know why. They both ran a dyno and everthing came back fine. One dealer advised me about a common problem with the fuel stabilzer cracking. I replaced it and it started alot better for two days and now I still have the same problem. That guess cost over $500. It has to be either a problem with the fuel system or something electrical, again the dyno came back fine. Im out of awnsers and tired of making costly guesses. Also while cranking no smoke comes out of the tail pipe(odd). Please help!