NeeklODN: Mph & Mpg

Only use the CC on totally level ground. Don’t use it in the mountains or on moderate hills. The computer is telling the truck, “Must Do 65 MPH No Matter What!”, so it will continually run either full throttle, or partial throttle to achieve the set speed, or to attempt reaching the set speed. This will be going uphill or down. You will get better fuel mileage without the CC. Don’t think you always need to be in a set gear either. Sometimes, it’s better to be going a higher speed with a lower gear, contrary to what one may have been taught. For instance, coming into an increased uphill grade pulling a 40K plus load. Speed may stay the same as you feed in more throttle, but your RPMs are dropping. Best to drop it a gear, get the RPMs up in the optimal range, and use less throttle. This takes a lot of practice and a lot of experimentation to reach higher and higher MPG results, but if you have the patience to honestly try it over several trips and months, you may be surprised. I calculate my fuel mileage by actual numbers, not a computer or off some dash gauge. Amount of fuel added, miles driven = fuel mpg.

Obviously I was doing this completely wrong because that's when my mpg dropped the most. I wouldn't wait for the auto shift to stop below 1100 rpms to shift into a lower gear going uphill. I'd manually downshift to keep the rpms up & maintain as much speed as possible on those uphills.

On the downhills, I'd just let the cc keep me at my desired speed with that Jake blaring the whole way down. At least I've gotten that part it down where I'm not fighting to keep my rpms around 1500. The lightweight can stay at or up to 2300 since it's a 12 speed. Unless I was told that wrongly.