Not nearly enough information.
What is the AFR being displayed when it's running poorly?
Since it ran fine before...I would look closer for vacuum and exhaust leaks.
Also all the usual suspects, proper wiring & connections.
An exhaust leak will tell the ecm it's too lean and dump too much fuel resulting in it running like poo.
A faulty CTS will tell the ecm that the engine is way colder/hotter than it is resulting in the incorrect AFR and running like poo.
Everything has to be correct especially for a "self-learning" lmao system.
If WBO2 data is incorrect it WILL run like