suggestions

I just got a 99 Tahoe LT 4 door 4x4 last Saturday and I've started doing some maintenance to it. It has just over 209,000 miles on it and it sat for a year and before that I'm not sure. So far I have done new e3 plugs, 8mm wires, cap & roter, map sensor, maf sensor, egr valve, acdelco serpentine...