Tach Sorta Responsive

So, I put a new tech in and you can see that it is getting some sort of signal in that it goes up with reving. Problem is that it has a slow response so when it reads 2000 its at about 3000. Also, the needle stroke isnt smooth in any way, actually its extremely choppy. I have rewired it. Maybe the power flow meter on the spark plug wire is bad? But it is brand new.

Thanks