I noticed that when I put the tow mode on the truck from the performance mode that I lost the high idle. Do I need to re adjust my tire size when changing tunes?

I have the latest download on my Predator and was wondering if it is normal for the truck to be really "jerky/choppy" with the cruise control on ? Ive had the programmer for a week now and can't use the cruise control because of the way it jerks the truck around, almost like it keeps tapping the ...