Ok, this sounds really weird but here goes. All my stock dash gauges have been working fine until recently (speedo and gas) my gas gauge started working strange. For some reason one of the idiot lights (then red "gen" one) has started coming on, I dont even think it is connected to anything because I have a one wire alternator (was put in years ago), but needless to say when I pull the light on the gauge cluster for the "gen" light it freezes the gas gauge, it wont work. It doesn't drop straight down (which has happened before when the sending unit accidentally came unplugged in the trunk wiring harness..lol) it just doesnt move
I put the bulb back in and everything works fine, but the red "gen" light comes on.
Any ideas on what is happening??

Do you have the diagram(s)?
Check this out while I do the same. Look for something that's common to those circuits....even grounds....
http://www.gvtc.com/~rlaa/Electrical/68_3.JPG
http://www.gvtc.com/~rlaa/Electrical/68_4.JPG
http://www.gvtc.com/~rlaa/Electrical/68_1.JPG

I would agree with 'dirty' ground(s). Is this car with 1-wire alt using an aftermarket wiring harness or original harness?

If original harness, you might make sure the OE regulator connector has both inside wires jumpered together and both outside wires jumpered together for starters.