I have a 2007 dodge nitro heat 3.7 v6. so my car started idling rough and shut off. I tried to restart it and it would kinda start but immediately shut off. if I put it in neutral and rev it at 2000rpms it would stay running but as soon as I let go of the gas it would chug and shut off. after a couple of minutes, so I changed one fuel injector with it just stop misfire but still shake and not stable on idle .no misfire shows on scanner monitors,.. does anyone have any idea what is going on?