I've noticed my Tach reads at least a thousand RPM's too high when driving. Even at idle it reads higher than it should. The previous owner says it has 3.73 gears, I don't think it does. At 80 mph it registers 4000 RPM's but the motor doesn't sound like it's more than 3000. The Tach is driven off the distributor so how could it be so far off? The distributor is new, so I'm wondering if the module isn't correct for this car? Thoughts?