Night time down grades.

I'm not going to argue about

On my truck with cruise on it will coast down hill then slow down till its 3 under then scream at max boost to get back up to speed. Common sense says you get better fuel mileage by letting her roll then slowly get back into her as you get into the next hill, now I can't say that about the newer trucks with automatic transmissions connected to GPS. I'm not sure how they operate. So I can't get into an argument about it

 

I set mine to yell at me when I'm 8 over.

 

My CAT engine's cruise has a program that does something like this. I don't use it; I manually modulate the throttle when I get worried about fuel economy as it relates to terrain.