I have a 17 1500 5.3 and love it. First thing would be to change out all of the fluids unless you have great proof that it was done correctly already. drain and fill coolant, oil change, drain and refill brake fluid. Tranny pan drop, filter and re-fill with Amsoil, no additives. Rear diff oil, and transfer case too after the others, soon but not urgent. If you want WAY BETTER shifting and throttle response, and to shut off annoying AFM, get a DIABLEW TUNE. Clean MAF properly and change the factory CAI filter. I have 64877 miles on mine and stay way ahead of maintenance intervals and the engine is very smooth. The AC condensor and negative battery cable internal corrosion are frequent trouble spots. . .