This is normal. You will also hear the servo motors close the A/C dampers.
????????????????????Armadaof1 said:If you dig into the manuals you'll see a few reasons for the computer increasing the idle - normally due to an electric or mechanical load (air conditioner is the big one). The truck also idles fast until warm.
If it bothers you - you can always go to NAPA and retrofit a carb and a manual choke.