2002 Chevy Silverado 1500 z71 106k miles. A little while ago my service engine soon light came on. I stopped by an auto parts store and had them hook up the code reader and they said it wasnt returning any codes. Now that the mornings are getting much colder here, when I start it first thing in the morning, it doesnt idle up like it should and falls down to about 500 rpm and every few seconds sounds like it is going to die. I can drive it for about 30 minutes and it still has the same problem but after that, it seems to do fine the rest of the day. The other day, the service engine soon light came on again and this time started flashing...which according to the manual means there was a misfire detected. Any ideas what could be causing this problem?