Don't quote me on this but I beleive I seen in another thread.
It's easy to use the high idle feature (as long as it's enabled: If it's not, go to your dealer and ask them to enable it with the DRBIII. If they don't know how, it's under engine and it's under transmission. Just scroll down to 'enable high idle feature' in either section).
Your foot has to be off the brake and stay off the brake; just put on the park brake. Transmission has to be in park or neutral.
1. Turn on the cruise
2. Push 'Set'
3. Pushing 'Accel' should ramp it up from 1100 rpm to a max of 1500 rpm (Using 'Decel' will bring it down from a max of 1500 to a low of 1100). If you just tap either button, you should get 100 rpm change for each tap.
4. To turn off: Just tap the brake pedal, turn off the cruise, hit cruise cancel, or drop it into gear (if you do this slowly, basically just moving the gear shift around in neutral it will give the ECM time to drop the rpms before you LAUNCH your truck. You will know when you have moved the gear shift enough as the rpm will drop fast, even though the transmission has not engaged yet).
DC only wants the auto trucks to have this feature. It can be enabled on manuals, it just takes a bit more to get it to work... ... I am still finding out if they will just enable PTO control so it will do the same thing.