Had a chance today to work on the truck.
Went to the auto store and had them scan it even though no check engine light was on. There was a code!
The code was for a bad o2 sensor, though it was for the one down stream, not the upstream ones.
So long story short I changed out that sensor this afternoon. I'll keep an eye on it over the next couple days and see if that fixes it. I'll keep you posted.