I can hear a small squeak or chirp when my Taurus sits idle, and lately now when I go to start the car it will sometimes start right up no problem and other times it will slowly turn over before starting. Other times it will slowly turn over and not start, and when I wait a few seconds it will slowly turn over again and start or it will start right up with no problem. I replaced the starter last year and the battery 5 months ago. I was told it could be the "camshaft" or something? Please help me answer some questions!