After replacing the purge canister valve sensor the car turns off after stopping and also has some trouble with rapid acceleration?

The car has check engine light. The scanner said it was the purge canister valve sensor. I replaced it and the light went away for a day then came back. I took to a mechanic and was told it's a possible leak but not to worry until the car has performance issues. The car sputtered when it started twice but leveled out fine after. Now the car turns off after stopping and also has some trouble with rapid acceleration.