Hard transmission shifting and code P0122
 

Got a 96 Blazer automatic 2wd. About a year ago it was shifting kind of hard from 1st to 2nd gear so I replaced the throttle position sensor and it made the trans shift like new again. Apparently this is a common problem, the TPS goes bad so the trans assumes full throttle and shifts harder. After a year of shifting great, today it started shifting harder than ever before. The whole truck would shake when shifting from P to R or D, and when it shifts up from 1st to 2nd. After driving it for a few miles I shut the engine off and started it again, and it went back to shifting normal. Check engine light was on (but it always is due to the evaporative emissions bullcrap code) but when I got home I scanned for codes and got "P0122 Throttle/ Pedal Position Sensor/ Switch A Circuit Low Input". When I replaced the TPS I bought the cheapest one I could find. Do you think I need to replace the TPS again? Or could there be something else triggering that code. 99% sure the trans isn't the problem. Thanks in advance for any help.