Sudden and drastic drop in MPG?

[flyrv9]

Why not try this and compute your MPG and leave the computer reset stuff out of the equation for now. Fill the tank and reset your trip meter. Drive say 300 miles and then refill the same way you did the first time and then do the math.

When we took our trip out west last Sept we calculated our own MPG and got reasonable numbers.

 

[st8rocks]

I haven't reset my MPG meter since new and now I have 17k on the truck. It normal reads 18.5 BUT when I take it offroad it drops to 17.5 granted I'm only doing about 50 miles offroad in 4L. It takes FOREVER to get back to 18.5, at least 1,000-2,000 miles of normal driving.

So, it doesn't seem to take much to bring the MPG down compared to how long it takes to get back to the normal average that you have been getting. Maybe like one member suggested the truck idled for awhile at the dealer dropping your MPG now it's taking time to get back to normal.

PS I didn't read the earlier posts so if you are going based on calculations not the MPG meter....disregard what I said.:guitar2:

 

[carlomagne]

FWIW, I'm usually in the high 14s to mid 15s. Ill start worrying when it's in the 12s.