Im glad I found a forum like this for our vehicles. Out of boredom and some frustration I thought I'd list all the issues and problems I've had to fix on my Tahoe. I bought it about 4 months ago used obviously, it had exactly 100,000 miles on it. From the 1st minute I drove it off the lot I've had problems.
Any of these overly common??(I know a few are for sure)

1. Taillights and dash lights didn't work...Fix: New headlight switch $70

2. Fuel guage stopped working...Fix: New sensor in tank $370

3. Slave CD player stopped working...Fix: Used one off ebay $50

4. Intake Manifold gasket leaking...Fix: New gasket $300

5. Rough idle...Fix: Had injectors flushed(helped a little) $100

Thats all I can think of off the top of my head.

I bought a 99 Tahoe 4x4 2dr 136K about a month ago also. I can't say that I have had the problems you have, by any means. I have only 2 ongoing issues :

1) Mysterious, intermittent electric cutoff/then stall.
2) Steering is more like slalom at highway speeds and steering stiffens considerably when making 90 degree turns at slow speeds.