Originally posted by Samson
but how do you know which one is the accurate reading? the aftermarket tach could be the one off 100rpms.
that'd be my guess...
If you are really starring at the tach while accelerating... you shouldnt be taking off so fast... learn to listen to the motor... not stare at a gauge so you "think" you know what the motor is doing... when in all reality, both the stock and aftermarket tachs COULD be WAY off...
concentrate on the road and your driving, not a stupid gauge...