Stock Tach is not reading correct RPM

[herbieS13]

I have a s13 sr swap w/ power fc d-jetro, the stock tach and the RPM reading off the pfc commander is off by as much as 1000rpm in higher RPMs idle - roughly 2000rpm stock tach and pfc readings match but anything past that the readings off the commander are roughly 500 rpm higher until 5000-5500 then it climbs to as much as 1000 higher than the stock tach, is there any fix to this? Or should I start shopping for a new tach?

edit:::
i have an s13, 89'

[Steve Lloyd]

you need a dual cam tach, the SR in an '89 won't read properly. The tach is easily swapped so you can retain your odometer if you care, or else just get a dual cam cluster and swap it in.

[herbieS13]

awesome thx