[jsbihn]

Egan,
I am not trying to doubt your ability.
I am sure as you know that over time thing rub and wear and crack.

Case in point, my sudden gas smell from my truck.

What I am saying is usually that is the big one with anything aftermarket.

As for Guru's comment, I am not am electrical wiz with these trucks, and not sure what all is wired to the stereo fuse and to other lines (ie. like the stereo wheel controls or whatever) but it does seems to make sense versus pulling out the head unit.

Given, the only thing that makes me wonder about any of these checks and fixes is that it is a gremlin. You stated in the OP that it does it intermittently, so who is to say that if you check the wires, fuses, head unit, and whatever that at that point it isnt acting correct.