Since I can't give a decent name to the issue, I couldn't really come up with a good title. Onto the problem...

So it doesn't matter whether I'm accelerating, cruising, or decelerating, what gear I'm in, etc. What's happening is this (it's worse while cruising) the vehicle will suddenly pull back with a loud thud and a drop in RPM. The weird thing is that when these 'hits' happen, my water temp gauge drops (never rises) then jitters around for a second.

All this takes place over the course of about a second. No lights or anything come on on the dash.

-RPM Drops
-Loud thud felt and heard
-Temp gauge drops
-Vehicle slows hard

Typically when I'm accelerating the hits are only felt as a loss in power (and the temp gauge freaking).

These hits can happen at any severity, and can happen once per drive or just one after the other non-stop.