I have an 03 Chev 2500 HD with 85k km. For the past month or so starting is hard espeecially in the cold - will often turn over many times before catching. Twice it wouldn't go at all and I've had it towed to the dealer and many dollars later I've got a new battery, new bleeding screw, new conductor for one bank of glow plugs and exactly the same problem. Seems to turn over OK. Last winter it started perfectly. Had the injectors replaced during the first year of use by the previous owner. Frustrated but love the truck. Could this be an injector problem? Dealer did fuel vaccuum test and fuel pressure control test and all OK. Starts perfectly immediately after first start.

Any ideas??

Bob