Tow haul mode

antman78 wrote:
The MH T/H setting controls the fuel injection timing. When the setting is set to "n", the fuel injection timing is optimized for normal driving conditions. This means that the engine will get better fuel economy and performance when it is not hauling a load. So, unless you are hauling a load, it is best to keep the MH T/H setting set to "n" for the best performance and fuel efficiency.

I’d say that’s almost wholly incorrect. On any light/med duty gas/diesel I’ve been around.
T/H in my experience, or any other “modes”, like sport or whatever, only alters the transmission programming/shift points and maybe exh brake application like on the 3.0 Duramax trucks.