Originally Posted by TheRabbit
Not to mention he probably lets it warm up a lot longer before he starts driving. I know when it's cold my truck idles about 20 minutes every morning before I leave.
I'd tell him it's also the colder air that the truck is having to push through. Once the global warming is in full effect it's get a lot better! lol
X 2 . . . That 20 minute idle or warmup is a mileage killer. My guess (?) on the air filter change is, he's wasting his time, but if it makes him feel good, fine with me . .
If he's that worried about mileage that bad, he needs to trade that Chevy off for a new VW Diesel . .