About a month ago, my factory tach pooped out on me and I tried everything to bring it back from the dead. Including checking all the wiring and fuses and connections...but I figure it was just getting old and let it be. So instead of replacing the instrument cluster and going through the hassle of wrong mileage and all that stuff I went out and bought a 5-inch Autometer Tach and installed it. It worked great and I was happy.

However, today when I started my 4Runner up this morning to let it warm up, the factory tach worked again!! But I noticed that under 3000 RPMs, the Autometer Tach and factory tach read about 200 RPMs off of each other (The autometer is 200 RPMs faster) but after 3000 RPM they read almost idenical. I was just wondering how accurate the factory tach is? I'm thinking maybe the autometer is more accurate since it's a direct connection to the coil? I dunno :D

wierd.

I actually had a friend with an 80 corolla that had the same thing happen. He had a factory tach but was a poser and wanted a big ol tach on his dash with a shift light. He got a real nice tach from a mail order catalog (can't remember where), and at lower rpm's it read higher then the factory tach. The funny thing was his was carbarated and didn't have a computer, but we still couldn't find where the stock tach was hooked up to the coil. We searched and searched and couldn't find it. Got lost in the wire harness somewhere.

Go figure.