my aftermarket tach works but seems to be "delayed and sporadc". it idles at the right rpm so i know i have the cylinder adjustment right, but it doesnt seem to be getting the correct signal because ill rev the car and my tach shows that i will be barely getting past 3000 rpm. i found that highly unlikely as it sounded a lot higher than that. its on a 92 h22a civic hatch with a chipped p28. the car has an msd blaster ss ignition coil. do i need to get an adapter for this aftermarket tach or is the tach just junk. ive tried hooking it up to all sorts of blue wires with the same result!