Recently my check engine light turned on. At the same time my speedometer went haywire, not reading the proper speed, and doing a dance back and forth. On top of that, the headlights and taillights will get dull and bright, the pulse sometimes it all goes back to normal but that is rare.
Please Help Me.

 

Sounds like your vehicle speed sensor is the problem. Do a search and a few threads will come right up with some great info.