I know this vibration issue has been done to death, but I tried a search already and couldn;t find any help... See, the truck had been sitting in my driveway unused for about four or five months due to work and travel constraints. Now that I am starting to use it again, I notice a strange vibration that was not occuring before. It happens under light load from about 35 all the way through 65 mph. In fact, it even vibrates a little just coasting down from say 45 to 30mph. No vibration present under heavy acceleration. So my question is: What would cause a vibration to develop from just sitting?? I spend a few hours underneath checking on the usual suspects like motor & tranny mounts, U-joints, frozen hubs, bearing, etc... but everything was fine and tight. Like I said, there was NO vibration at all before I stopped driving the truck for a few months. What could cause this?