Just got a new truck with the 6.6 duramax. Really like the engine, but is my first diesel. So I have a few questions if you wouldn't mind helping me out...

- What is the "fast idle" function for in the setup? Why would I use it/not use it?

- How long should I warm up the truck before I go, if at all? I read before with gas engines you can just drive slowly and let the engine warm up as you drive, is that true for a diesel too? If not, do you always warm it up, even in the summer?

- I've already found out that it's possible to get a bad batch of fuel. One take I had I got super crappy mileage, next top up my mileage was back to normal. Ever since then I look for the premium diesel, and try to stay away from #2 diesel. The manual says #2 is okay, what's your advice on fuel?

I probably have more q's but that's all I got for now, thanks.