More trouble with the truck

[txbass06]

So my truck has been dragging pretty good trying to start it the past week or so. Checked the red top which is less than 6 months old and its fine, alternator is putting out a little over 13.6v so I'm thinking the starter is going out. I'm assuming its the original starter and 14 years isn't too bad at all. Starter replacement is no big deal to me. But this morning, I got in it to drop my son off and after it fired up, the RPM's dropped to almost 0 then picked back up.

Got back home, killed it, then tried to start it again and it dragged like normal, fired up, then died. Tried starting it again and it did the same. Fired up, revved up to about 1000 rpm like always on start-up then dies. If I keep my foot on the pedal even the slightest it'll run just fine, doesn't cut out or try to stall and I'm stumped. No CEL or anything and I have no idea how a bad starter could keep it from running. Anyone got any ideas?