gauges acting up

I'm pretty sure most peoples' issues with gauges that resembled your symptoms were the result of a bad ground. Not sure where the ground is located for the gauge cluster though, so hopefully someone who's had the issue will chime in.

When my block to chassis ground shot craps my guages were acting funky, oil press would peg, volts would drop, water temp would go up and down. My issue got bad enough that the car would not start anymore and the fix for that (the block to chassis ground) also fixed the guage. I thought the guages were a sending issue as I found a frayed wire at the water temp. sender and wraped it with elec. tape...the ground wire fixed it though.

I think its just a time/heat over time soaking into the wire. I mean that ground wire sits fairly low and I am sure its not weather proof...I would guess just over time heating up cooling down in diff. weather will cause it to crap out.

If you have some wire (at least 8ga) make a jumper and attach it one at a time to replicate the key grounds. Like just hook it up to the batt. and to the block (like wedge it into the batt. ground and to a valve cover bolt) were its easy to get to but out of the way and go for a ride and see if its still funky. If its still bad move the ground off the batt. and to the chassis so its going from the block to the chassis (like a valve cover bolt and strut tower bolt) and go for another ride. The last one I would check would be the batt. and chassis as there is a little ground off the main batt. ground that goes to the front core support.

IF its still an issue the prob. very well could be in the cluster...maybe ebay a used one and see if it fixes it if the used one can be had at a fair price. I dont think I would put too much time/money into a cluster if it was bad though.