Gauges fluctuating, bouncing around

[Laneman25]

2001 Monterey LS190 with Volvo 5.0 GL, Chevy 305. Tach has a mind of its own, sometimes reads normal at idle, then goes up to 3,000 RPM by itself. Fuel gauge drops suddenly from Full to 3/4, then right back up. Volt gauge reads a constant 12.8 while running, but I don't trust it.

 

[Scott Danforth]

you have bad connections. start at the battery, remove, clean and seal every connection all the way to the helm. pay attention to the ground buss under the helm.

 

[Laneman25]

Thank you Scott