My 2000 neon starts fine but runs rough. It dies when the lights are turned on. The tach goes to zero a couple seconds after starting. A few dash lights come on, check engine light, door ding, etc. Battery posts clean. New Cam position sensor about 2 months ago. Battery is fairly new and tested good. Alternator tested funny -- too much voltage under demand. Tech thought it might be a wiring problem. Anyone have a similar problem? Suggestions greatly appreciated. Thanks!

 

Sounds like you have an electrical grounding problem.

 

Second that one. In class we had a factory stock Taurus which the caused a ground isolation that made the car run just fine but you honk the horn or turn the left turnsignal on and the engine turned off. Grounds would be my suspect.

PCM controlled voltage so possible PCM problem too. But double check all of your engine and dash grounds.