Fuel and oil gauges pegging

Typically the gauges have a no power position and will rise a tad with the key in the on position. As long as the senders are connected.

You can always VERY temperarilly touch the temp sender wire to ground and look for movement. (Safest with 2 people)
With key just in on position not running fuel and oil head to peg temp nothing will test the temp today ty if it was ivr in my fuel gauge was bad would all gauges still spike if I remove feed wire ty