As the title says, my tach reads high. I know this because both my ECU and the dyno's tachometer read significantly lower. When my OEM tach reads 8K, the true RPM is only about 7300. The discrepancy is consistent and repeatable. I have a procedure for changing the RPM at which the buzzer sounds -- is there a way to calibrate the tach?

Also, what's a good self-contained shift light? I don't want one that requires extra modules and pills to function.