76 280z gauges not working.
 

I just recently picked up this car and the following gauges aren't working. Tach, tempature, fuel level and oil pressure. I looked at the FSM to try and find commonality but I still haven't found the problem. Anyone else ever have these gauges fail together?

You must really like oil pressure or you have two oil pressure gauges! All kidding aside, looking for commonality is the right thing to do.

I don't have my FSM with me right now (on holiday) but I'd start with the fuse or fuses. If they are good, make sure they are making a good connection to the fuse holder.

Once you get past that, IIRC, there is a common ground connection. Check that. Connectors are another point of failure. They can get oxidized (dirty) and fail. Sometimes just disconnecting and reconnecting will fix things. A word of warning though, if that is the problem and all you do is reconnect, the problem will soon return. Clean the contacts with some circuit cleaner.

I just wish I knew where all of the relates fuses and fusible links were. I'll keep checking.

Well, I followed the tach circuit from the battery to the tach and I must have wiggled something just right because now it's working. When I traced the other gauges, all seemed to be in order but still nothing. I'm assuming at this point that the gauges themselves must be the culprit. I'll keep you guys posted.

Wellllll, I spoke to soon. The tach works when it wants to but no often. The other gauges needed to be replaced and all is well now except the clock.