so about 2 months ago my truck got repo and 5 days later i went and got it back. 3 days later and it wont start,switch the battery and nothing. it use to turn on with a jump but after 2 days it would not start w a jump. took it to a mechanic and they changed the following ( fuel pump. starter , fuel injector? and im not really sure what else bc my dad is keeping up w the mechanics but anywho they believe its an electrical problem. not a car specialist but they said they would pour gas down something and it would start but after you turn it off it doesn’t start. i don’t know what it could be or what not any help? or advice?