ive got a 2002 chevy 6.6l deisel, im having problems getting it to start, the engine turns over just wont fire, the only way it will start is if i spray some brake cleaner down the intake, once it is running it runs great until you shut it off, i just took it to florida for a trip and had noproblems with it starting down there, on the way home when the weather was a bit colder had the same problem, ive checked the glow plugs and they are all fine, any suggestions