My car wont start and its not the battery or the starter or the alinator, it sounds like it wanna turn over but when l try to jump the battery l get it started and then it will turn off. anyone have any idea what l could do. l tried heet and that didnt help and l have a half tank of gas. Please Help Me.

well most likely it is the fuel and some times you have to drian it if there is too much water or trash in tank which happens alot in winter and when you run tank low if it will start and die then its not gettting fuel so also could be dirty filter.. also might be alterantor not working that is where all fire starts to crank so unless you have had that check by a tester cant say

so the car wont start on its own, but does start with a jump, then shuts off?

In that case, It would HAVE to be the battery or alternator since one of the two is preventing your car from starting without a jump. Your battery is dead since it wont start the car, and the car shuts off- because the alternator isnt charging the battery

so its the alternator

Try this basic test get a voltage meter set it for 20 volts DC place the negative lead on the negative of the battery then the positive lead on the pos post of the battery & with the engine off read the battery.Then perform the same test after ur vehicle is boosted & if the voltage is not about 12.7 or so with engine off that means battery is bad but make sure u use solid test points when testing it.With the engine running it should read from 13.7 & over 14 volts but if over 15 volts have the alternator & voltage regulating system checked.
Note that if the two readings r low that a loose alternator belt can cause the same low current test results.Also any bad rust or corroded connections within the battery, starter , alternator ,engine block ground or grounds or fuse junction posts etc can cause low readings or such starting or charging system failers.
A clogged or dirty gas filter could also be part of the problem here especially if it is not be changed on a reg yrly basis & you've run it with extreme enviormental conditions & over all temperatures or have driven it low on gas.Might be a good idea to change it & also run some gas treatment through the system & after a few tanks of fuel is used up change the gas filter again on it.

Hope that helps & best of luck.By the way if u disconnected the charging system is connections & cleaned them all throughout the system such as I've mentioned with a small wire brush , sandpaper , file etc l bet u see a big change in that vehicles whole electrical charging system.
Happy Holidays

Is your theft light flashing? The fuel will be shut off right after it starts if the theft system does not get disarmed.