Turned out to be the servo motor. More accuratly, the servo motor gears. One or 2 little plastic gears got stripped out when a very small rock got stuck in the exhaust valve (exterior) mechanism. $206 later, it's back to as good as new.
After seeing the interior of the servo motor unit, I'm glad I didn't buy a used one off of e-bay or a salvage yard.
Yeah, that's what I said, or maybe something a little stronger. A worthless little rock wrecked a couple of 99 cent plastic gears. Cost me 206 smackers. But like I said, after seeing what is on the inside of the servo motor unit, I'd never buy a used one.