When I start my car at idle the tack sits at like 2500 rpms when I know thats not how high I am actually idleing. When I drive it ,the tach shoots up to like 4500 RPMs and increases from there. I have had people tell me mach tach needs recalobrated, If it is that how do I recalobrate it . I appreciate any input.Thanks

 

my tach also does that but its hard to get an answer on that one. My old boss told me that there is an electrical component that all the gauges circuits are run through and that sometimes it goes bad and cause some of the gauge readings to be screwed up. But i have no idea what the part is called or where it is. Hopefully someone can help us out

 

A friend of mine just told me that he had the same problem, and that he just replace the tach with a junk yard one ,and now it works fine. So I will probably go to the junk yard and get one for like $5.

 

I had the same problem with my tach. When I took it out I realized part of the circuit board was fried. I did the junkyard deal and got one for 10$ in perfect condition. Those Tachs cannot be recalibrated as far as know. They come calibrated from the factory for a 4,6 or 8 cylinder engine.

 

Your tach can be repaired, costs around $80-$90

http://dandmrestoration.home.mindspring.com/tacho.htm

http://www.tachman.com/