just wondering if their is a common problem with the guages on an 86 Z28. my speedo and alt guage are all that work. any help would be great

 

Did you check your fuses? If not that, then you need to do some tracing. The gauge cluster connects directly to a plug that's mounted to the dash behind it. There is a flexible pc board that's mounted to the rear of the cluster. That "board" could have corrosion on the copper contacts where it plugs in, where the individual gauge mounting nuts contact to the board for connection, or the board could be cracked which breaks the connection from point a to b to c. It's possible that some of the corresponding gauge supply wires that connect to the dash plug are broken, but given the number of gauges that are out, I see that as a less likely culprit.

 

If everything is original, check sending units for water and oil pressure. Tachs require a little more digging, I often see guys after motor swaps not reconnect negative ignition source to the tach....

 

Your speedo is cable driven, the battery gauge reads system power.
Another possibility for the other gauges is if you had a bad ground to the cluster.

 

At least on 3rd gens from what I've seen is that there is no reason for gauges not to work...they may not be as accurate as a mechanical ones, but they should work. Sending units can, and do go bad, and if the previous owner did some tinkering, they may be just disconnected.

 

all sending units are hooked up under the hood and the tach wire is also hooked up and plugged into the tach side of the dist. haveant had time to pull the guage cluster and check it out