if your truck is an auto do this to see if it has already been enabled. start your truck, leave it in either park or neutral with the e-brake on. turn your cruise control on, press set. it should idle up to 1100 rpm or so. if this doesnt work i think this is the tsb, Cold weather idle TSB 18-004-04

 

I have a 6 speed and I tried that but no work. Is there a tread that I can go to see what options I can do with my truck?

 

My trucks (07, 5.9, auto) idle increases on its own after about 8-10 mins of idle time when I first start it up.
Do you folks run air compressors and such is that the reason for activating the fast idle feature?

 

try this link. should work for you.

https://www.dieseltruckresource.com/...=120288&page=2

 

If it's really cold mine will idle @ 1000rpm right after it starts until I press the brake, then the rpm will slowly drop down to 750. Semi-cold the high idle kicks in after a bit of idling.