2 step
 

Wondering if you have heard of this. My sons S-10 has a MSD 6AL and the matching 8732 rev control. Every so often, 10 runs or so, not consistently, he stages, pushes Tranny Brake button and the rev control does not work. Engine goes to converter rpm, not set rpm. MSD says they have never heard this but 2 other cars we know have done this.

what's the cause? Do you know?