99 cvpi

if the alternator is bad or is going bad does the check engine come on have this ever happen to anybody

No, a bad alt will not cause a CEL.

Thats not entirely true. Low voltage as a result of a bad alernator or battery, can cause any of the cars systems to operate out of spec, causing a CEL. I had one that made the ABS light come on and the CEL.

Let me put that another way, there is no CODE in the PCM for "low alternator output".