Ok I swapped my old vortec box outta my 2000 S-10 4x4. Now the tach is off, and I played with all the tach multipliers nothing has helped? The engine is 4.3L V6 too. Do I need a cluster outta a 02 to be compatiable with the new pcm?. It seems that the pcm needs to put out more pulses. The stock seting is 1 in the tach box, and increasing the number only makes it worse.

Thanks
Kurt