I bought a used park ave a couple weeks ago and.

I bought a used park ave a couple weeks ago and it drove fine, no issues. The service engine soon light came on and has stayed on so I had the codes read. TPS and purge valve, I replaced both and the car will not change up gear until 3800rpm let off the gas and it changes up. Thought it was the tps so tried a different one, unhooked neg to battery almost a hr than it started with a high idle. Thought wire was loose on the plug cause clip broke replaced, reset again and back to the shifting gear thing again. It idles ok in park/neutral. Goes into gear good but has a pull when let off brake like it wants to go on its own. I have ideas but need opinion of what the problem is now.