help!!

KAM1

if somebody has had a similar problem and has found an answer, please let me know!! everyday i am having to jump my car. all the lights will turn on and even the fob will work until i try to start it. once i try to start it it tries to crank and then dies. it has a new battery and starter plus the alternator has been tested and everything checks out. i’ve brought it to the mechanic 3 times now and it will work for a few days and then stop. i’m thinking it’s something electrical but i’m not sure what.