I have a 1999 Yaris, the battery used to die if I hadn’t driven the car for a few days. After I charged the battery the car would jerk considerably and low speeds and up to 30mph, while it would also take longer to pick up. This would eventually clear if I ran the car for long enough.
I therefore replaced the battery there was still a considerable jerking at lower speeds which also cleared after the car had been run for a while.
Why does this occur?