I have a 92 lx coupe 5.0 I am trying to install a aftermarket shift light that has the digital rpm read out I hooked it up straight to the coil and it is showing the wrong rpm so I took it too my buddy's car hooked it to the coil and it worked fine so I came home hooked it too the coil again still same problem so I hooked it where my aftermarket tach is and still showed wrong rpm.