I've got the whole car wired with the 2002 z28 harness. The drive train is out of my 1998 z28 which has its original computer and own engine harness from the 98. The dash is from the 02. And I can't get the gauges to work. When I start it the oil pressure gauge will come on but then shoots up to max pressure but none of the other gauges work. Any ideas? Maybe a ground problem?

 

I would say you did not wire it for the newer 02 cluster. As for the oil pressure, probably a faulty oil pressure sensor or pinched wire. You posted in wrong section, so probably why you have not got any help.