could a bad alternator make your car jerk and missfire?? tach and radio went dead

 

No an alternator converts the mechanical energy from the battery into electrical energy. Once you start on car by battery alternator uses the electrical energy to run the car. The battery is then used for small size accessories while it is charging.

 

so what would make my tach drop to zero, my radio shut off, and my car start missing and jerking??

 

Any codes?

 

yes it could cause problem there are rectifier diodes in the alternator, if some go bad the alternator might still work sort of and could cause radio/electrical interference with the ecu.