Car shifts late and hard

duckdodgers

2000 cavalier z24 2.4 170k autom 

At first I thought this was a transmission fluid problem but had it checked and it's full. This may be a combo of 2 issues. At first it shifted so hard I couldn't really drive the car. AutoZone computer said the tp sensor needed replaced. I got the tp sensor and the issue did change for the better in that I can drive the car now but there is still a problem.

Its an automatic 2000 cavalier z24 2.4. shifts hard into drive and through the gears, although a bit softer into 3rd and 4th. The weird thing is, and this is how I manage driving it with less issue, is that if I slightly let off the gas real quick and push again when I think it should shift normally, it does. Every time. If I don't let off the gas and push again slightly it will shift late and hard which I imagine isn't good for the trans to deal with. 

Any advice would be appreciated. Not sure if it might be something like a speed sensor or what. I'm an auto repair noob. 

Mr_Shiftright

Probably Autozone used a simple code reader, so you might need to access a professional scanner that can go deeper into the car's systems. Or you can get external testing done at a transmission specialist---might be some pressure issue going on here.