What defines the minimum RPM when not depressing the throttle pedal? In 2nd gear starting at about 1000 RPM, my dad's 5.3L with a 4L60 and pretty stock OS slowly creeps up in speed. The RPM and speed will slowly increase until he has to ride the brakes to keep the speed below 25 MPH. I assume that the idle table desired RPM have nothing to do with this as the truck is above 10 MPH. Is that correct? Is there some minimum airflow that the computer is commanding and pushing the rpm up to?