Welcome to the forum Chris.
Has a tune up ever been performed on your Tahoe before?
When you say idling rough, does the rpm gauge show the rpm'* wandering a bit not steady?
If so cleaning the IAC intake air control, might help by removing it, and cleaning the pintle,spring area, with throttle body cleaner and re-install it.
Generally around those miles, I would want to have some new spark plugs in my rig and spark plug wires as well and install a new fuel filter.
The dealer would probably recommend an emission service as well, where they hook up special commercial cleaners to the fuel rail and let it run through system.
I use Techron Concentrate 2x bottles to a full tank and take it for a solid 2 hour + highway run at 70mph if possible.
Chevron Techron Concentrate Plus, 10 oz: Automotive : Walmart.com
Others have used Seafoam Motor treatment added to fuel with good success.
When do I add Sea Foam Motor Treatment to my fuel tank? - Sea Foam Sales Company
Hope this info helps.