I have an 03 roush 4.6L NA car, only mods done to it are CAI, Accufab 70mm TB and intake plenum, and exhaust. It threw a code last week for cam position sensor because it would backfire on start ups so I replaced that. I got a new ac system installed today, Just picked it up from the shop and on my way home getting it above 2k rpms it would start backfiring and hesitating. I came up on a stop sign and my car died and won’t start back up. I have all my lights and radio still works, the car just won’t crank over. What could this be? I have a new alternator in the mail should be here tomorrow.