I have read that for folks that do not use their trucks much starting and running it for short period of time is actually worse that letting it sit. The reason being that starting and running it creates condensation internally and without longer running times at increased RPM's it will not allow the draft tube/PCV systems to properly expel the water.
This will allow the condensation to build up in the engine/ exhaust and cause issues over time.
I would recommend Tim's advice and use Stabil then allow a run time of 10-15 minutes to make sure it is in the fuel bowls of your carb(s).
