My car runs fine cut it off and it is slow to crank or will not crank on 1999 Pontiac Grand Am

I can go to wal-mart and my car starts fine when i leave i can go to another store but maybe only be there for 5 minutes and my car slowly cranks or wont start have replaced top of motor radiotor and the fuel pump and battery what can it be

2 answers
Your car does not like for you to shop any store but wal-mart!

My guess is you have a starter motor problem.
I agree with wetry but you did not say how you got it going if it starts with a boost then check charging system