A month ago my instrument panel lights went out.. a week after that my turning signal lights went out... last week my car began sputtering and cutting off and needed to be jumped off... a mechanic shop diagnosed it as a bad alternator.... so I replace it. a day after it had been replaced.. it sputtered and cut off again... so I bought a new battery... so I now and a new battery and alternator and my car is still doing the same thing it was before I had those things replaced.... shutting off and having to be jump started... after its jump started it will on stay on a few minutes before cutting back off. What should I do now?