Review on Auto Meter 3707 Sport Comp Tachometer by Austin Cejudo

I bought this tach for a '94 Mustang GT that has an ignition coil timing system because the fitment manual indicated it could be used in this application. From the moment I installed it, it never worked properly. The indicator shows very low readings or nothing at all. I've tried many things to get it working including changing the coil connection (pigtail) and replacing the coil itself. Nothing helped! Contacted Auto Meter and they said it looks like the sensor needs calibration and sent it to them. I sent it to them for $10. Got a new one a week later. The new one did too. Well, now that I've lost $127 on the tachometer and $10 on the return postage, I will never buy anything from Auto Meter again! I probably should have gone with SunPro.