1988 Suburban, 350, tbi, auto, w/o AC, 2WD.

1988 suburban, 350, tbi, auto, w/o ac, 2wd, 89,000 miles, gave me a code 45, running rich, new plugs, cap, rotor, read book, replaced EGR, MAP sensor, stil have'nt replaced oxygen sensor or TBS? On the side of the throttle body. It will not idle, and dogs when I give it the gas, I have to keep pumping the peddle to get it to sort of run. To hear it. Sounds like it's missing , but I tuned it up. Except for the wires, the old plugs smelled of gas with some oil on them, It always started and ran with no problem, I never use it, it just sits, it was my fathers, I ran it, and let it idle to keep the battery charged, then one day I noticed it died, so when I restarted it , it threw a code 45. But it still started, but it did'nt start quickly as before, but it still idled, then another day I started it while working on my other vehicle I noticed it had died again, and this time starting it was had and gave me all these problems? Oxygen sensor? Throttle body sensor? Everything else they stated in chilton was changed? Anyone know this problem? Have throttle body rebuilt? Or what? HELP !