05 VW Passat Turns over, won’t start

this car has been a problem from the beginning… engine light on, codes say misfire. Started overheating so I replaced thermostat. Still had hardly any power or acceleration, engine light flashes a few times every time I start car, now all of the sudden it won’t start. It’s not the battery because I tried to jump it, all the lights come on fine and everything it just won’t start. Could it be fuel injectors? And if so how would I know if they need replaced or Just cleaned?