Gas mileage with tow/haul on lifted trucks

I got 3gen tundra limited with 5inch lift on front. Its gets 11.8mpg average when I drive it normally but when I turn tow/haul its getting over 14mpg. Is it normal?

 

Yeah sure !

 

What it does to the truck? Trany shifts different? Something else?

 

I guess it’s possible since mpg is really rpm*throttle position. You can have more throttle opening at lower rpms when you’re loaded. This is why towing in 6th and burn more fuel than towing in a lower gear.

 

It would be about the same with or without Tow/Haul mode. What mileage are you thinking that you should be getting?

 

I was getting average 11.8mpg for 600 miles , than I tried to drive with tow/haul on for last 100 miles and it is 14.4mpg now. Same driving style, same commute, about 60/40 hwy/city.
And this is pretty weird cause I though it suppose to be opposite - worst mpg with tow/haul on.
12mpg is kind of normal for winter driving lifted truck. I keep it in the garage so no long warm ups