Poor acceleration

Thanks for this site to ask questions! The car doesn’t start as easily as it used to. Also, when I attempt to quickly accelerate, it bucks and nearly shuts off. However, if I let up on the accelerator and ever add so gradually press the pedal, it will accelerate slowly. No engine codes! I tried changing the throttle position sensor but no change.
I’m lost and sure I can change parts but I’d rather not throw a lot of at it because I’m planning to sell it as soon as I can get it running better.
Your time is much appreciated!