C-9 Starting Issues
Well you wont believe me but you need to change your engine oil. I have an 2004 D6RII that would spit and sputter and not start when it was cold out. After $3000 dollars of injectors and three days of a field service tech on the phone to his guru's the solution was to run a lighter weight oil.
I too ran 15-40 in that tractor as well as every thing else i own, but not anymore. In your operators manual (who reads those anyway) there is a small paragraph that tell you its recommened to run a lighter weight oil in colder weather. So the solution is to run 10w30 or 5w30 when it is below 40 degrees. There also is a plug above the engine computer that needs to be changed when you switch weights of oil so the computer knows what it is running. I switched to a 5w30 when it gets colder than 40 and I run in temps down to 0 and it starts and runs smooth. I know it sounds stupid but it works.
As for the intake heater it has one but it may be turned off in the computer, a service tech can check that. email or call me if you have questions.