I don't understand what the deal is with tach spikes on the V3 boards...I dont use any shielding of any kind on my tach input wire, I just tapped into the crank sensor signal wire at the stock ECU, and I have no spikes what so ever...Only difference is that I run the version 2.2 board. I really think it's something in the design of the v3 board that either doesnt like our tach input signal from the crank sensor, or its just that sensitive.. If you guys can try this, maybe competetly disconnect th crank sensor from the stock ECU, ground it to the MS main ground, and try using different voltages to power the sensor. Try 5 volts, then try 12 volts. You wont damage the sensor with 12 volts. I'm wondering if the output voltage from the crank sensor is either not enough, or maybe too much from the 9 volts stock. You can get 5 volts from many places off of the MS PCB, and 12 volts is simple to get anywhere from the car or MS power feed. Try 5 volts first, and see what happens, then try 12 volts.