Sounds to me like your valve seals are starting to leak a little. Smoke on start up and then goes away while driving is a sure sign of this. The fact that the truck sit more than it is driven could have lead to this condition.
The solution is two fold. Dont do anything, and I doubt it will burn enough smoke to even make the oil low between oil changes.
Replace the valve seals. All you will need is an adapter to allow you to pressurize each cylinder. A spring removal tool, and new set of valve seals.
Remove both valve covers, and valve lifters. Pressurize one cylinder and remove the springs. Replace the seals, lube well, and reinstall the springs.
CAUTION! Do not remove the springs without the cylinder pressurized. If the valve falls into the cylinder, you will need to remove the head to reinstall it.
Wednesday, August 16th, 2006 AT 3:36 PM