Strange problem...could it be related to Speed Cal?

I put the Speed Cal on a couple weeks back. Since then, once in a while, the speedometer bounces. Today when I was driving home, the speedometer did not work at all. When I got off the highway and stopped, the check engine light and battery light went on and the car began to run poorly. Next time I had to slow down, the car stalled. It proceeded to stall 8 more times til I got home. It seems like this only happens when I push the clutch and brake in at the same time. The reason why I ask if the Speed Cal is responsible is because it was not working. When I got onto my street it began bouncing again and the car did not stall. However, it did jump the way it did when I got off the highway. The radio never turned off when the car stalled.

What is going on?

Thanks for looking.

bullitt_5135 said:

Probably intermittent power to Speed Cal....

Click to expand...

I am not good with electronics. Can you elaborate a little on this? Are you referring to the red wire that connects to the cigarette lighter? I ask because I had some trouble with this. It seems like the scotch lock is ineffective because the blue wire for the lighter is much wider than the red wire for the unit, causing the red wire to not hold in it. Also, why would this make the car stall only when I use the brake and clutch at the same time?