Well, the 4WD isn't strictly reactive - you'll notice that it kicks in every time you make a start from a dead stop, at least 15-20% torque is sent to the rear wheels. If it's in 2WD, it's operating in FWD mode all the time, which should be more efficient.I read your other post, but thought that my follow-up fit better in this thread labeled MPG.
So I've read to keep it in 2WD instead of Auto. But PROVIDED THAT Auto doesn't ever kick into 4WD mode, is it any less fuel efficient than 2WD mode?
In other words, does the fact that it is in "standby" mode affect gas mileage? Or is it just that the act of occasionally switching into 4WD mode, and you're not realizing it, is what is affecting mileage?
That's a really good point.I find that after the 3rd oil change mileage gets better. Also to consider is that winter blends of gasoline aren't as fuel efficient. Cars in general aren't as efficient in winter.
I actually wondered why car makers don't let customers know how many miles it will take till they see their vehicle getting the gas mileage it was rated for. Under 4k for 1500 miles for engine break in is great but how many till we see whats on paper will help.That's a really good point.
When the ambient temps are low, your car takes significantly longer to get into its "efficiency zone" (i.e. fully warmed up). Add in winter-blend gas, and sometimes much lower temps, and you've got a recipe for a good 2-3MPG reduction.
Generally most engines aren't completely broken in until 8000 miles or so. Nissan says to go easy on it (keep the RPMs under 4K) for the first 1500 miles, but that doesn't mean it's fully broken in at that point.
What I think will end up hurting the PF the most in terms of consumer perception of efficiency is that the mainstream models all seem to come with remote start. Remote start is the sworn enemy of gas mileage. If your car is sitting idling, it is burning gas and achieving 0MPG for sustained periods. Factor that into the average for the tank, and it's a death blow.
winter tires are much heavier than regular summer or all season tires.Another factor is tires. Tires alone can cause a drastic drop in mileage. As much as 5mpg (but likely not for regular tires - more for high performance track tires)
Winter tires I find generally decrease mileage as well. The winter tires + driving in snow and ice = another 2-3mpg drop. So add that with the gas blend and the engine that hasn't broken in and you could see a drop in mileage of 6mpg or more because it's winter.