Hey, I think my tach might be acting up. But, I could be wrong. Anyone with any 1st gen's out there mind telling me what their ls400's idle at? Because mine (warmed up and air conditioning off) is idling at the first line, which would be about 250rpm. I don't believe this, at all. So, am I correct in assuming that my tach is off, or is the ls400 just that awesome?

 

I have been through 3 instrument panels since I purchased my 1st gen ls 400. Every time I had to replace it, it was only the tach that was out. The one I have now reads about 400 at idle when its cold, and about 250 once it warms up. So I believe your tach is a little off. It should idle at about 600 once its warmed up (I have had a couple that worked right). I have also noticed that it is exponentially off its mark too. 3000 rpms is probably more like 4500 rpms on my tach. 2000 rpms is more like 3000 rpms. Can't tell you why, but you can replace them fairly easy, and there is a company on ebay that will re manufacture your old one for 150 dollars or so. I think there is 5 screws and two wiring harnesses to deal with on the whole project.