[rpmerf]

Each of these issues is going to stem from 1 of 3 things.

Bad sender. For coolant and gas, you can touch the wire directly to ground and it should pin the gauge.

Broken wire or bad connection. Either an ohm test or continuity test on the wire that connects to the sender, and the plug that connects to the back of the gauge. Make sure all connections are clean.

Bad gauge. Should be able to wire them up independent of the gauge cluster.