It's possible the valve guide has slipped down, displacing the valve seal. This was the case on my #3 and #4 cylinders. The valve guides DO slip sometimes, and when that happens, the valve stem seals pop off because there's nothing to hold them in place. The valve guide needs to be tapped back into position and a retainer clip installed.

Read my report and see what you think http://www.mightyram50.net/vbulletin...ll=1#post26192

The repair, itself, was not expensive...$25!...it's the head gasket set that's the primary cost.

You can check to see if this is the condition your truck has by noting the seals' height compared to the others (photo on page 3 of my thread).