I have a 97 f-150 4.2. When the temp gauge starts to increase the amp and oil gauges top out. When it reaches full temp., the temp, amp and oil gauges bottom out. I replaced the sensor but that did not help the problem. Any clues on what the problem is.

 

With electrical problems it's good to always start by cleaning battery cables and checking fuses/fusible links. Next I'd look for an antifreeze leak (antifreeze conducts electricity and shorts things out when splashed around - wash/wipe dirty wires under the hood). Next I'd check sensors and I'd look for a crossed wire or a problem in the dash cluster. Could also be a computer problem.

 

Or if you have an electric fan - could be fan relay.

 

Thanks for the info. when I get a chance I will try your suggestions.

 

Do your lights get brighter when this happens? It could be a voltage regulator problem.

 

That's sounds right. Voltage regulator affects a lot of electrical items in the basic accessory scheme of things. Starter circuitusually remains normal, etc. and electrical systems go crazy.