#2952, "Tach Spikes and Resets... Did you know..."
That if you've bolted/screwed down (or simply letting touch) your Megasquirt to a metal surface in your car, you've created a ground loop through the housing, which I've proven can create resets and can also create random tach (and other sensor) spikes.
If you're suffering from this situation, throw a towel or something undeneither your now un-mounted Megasquirt, and take it for a drive!
Joel Baldridge, ASE Certified Master Technician, Audi Certified Expert Technician