Success! - vibration is 90% gone. Finally had some time to work on the Tahoe this past weekend. I removed the intake and unbolted the throttle body again, and checked around for any loose connections around the engine and found nothing.
I'm pretty sure I overtightened the TB bolts originally. I got a torque wrench and properly tightened them. I also noticed the TB was sagging a bit on the bolt points. This time I held it in place while retightening rather than let it rest on the bottom bolts. After putting everything back together, the vibration reduced significantly, and after a day or so was pretty much gone. It's still there if you really feel for it, but that's probably just normal.
I don't know if it was the bolts or something else related to taking it all off and putting back on again, but happy that annoyance is gone. Hope this helps anyone else with a related issue. Maybe overtightened bolts, sagging TB, or just jiggling a few things like you know what you're doing and put it all back together. Worked for me.
I'm pretty sure I overtightened the TB bolts originally. I got a torque wrench and properly tightened them. I also noticed the TB was sagging a bit on the bolt points. This time I held it in place while retightening rather than let it rest on the bottom bolts. After putting everything back together, the vibration reduced significantly, and after a day or so was pretty much gone. It's still there if you really feel for it, but that's probably just normal.
I don't know if it was the bolts or something else related to taking it all off and putting back on again, but happy that annoyance is gone. Hope this helps anyone else with a related issue. Maybe overtightened bolts, sagging TB, or just jiggling a few things like you know what you're doing and put it all back together. Worked for me.