I searched around and never quite found this exact problem. A few posts that I found stated similar problems but they didn't seem to be what I am experiencing.

This is a 96 limited auto. When I am at highway speeds and push the gas it feels like a shudder coming from under the truck. It only lasts for about a second and then the truck accelerates out of it. It happens regardless of the transmission downshifting or not so in my mind that rules out the tranny. I was also getting a clunk sometimes when this happened but I greased all the u joints and the clunking seemed to get better.

The only other posts I found about this were talking about engine problems but this seems to be more drive line related. Could one of my u joints be going out? The truck has 190k miles on it, 33" tires and I tow my boat with it so I wouldn't be surprised if the u joints did need to be replaced.