If the gauge goes to zero momentarily and then back to full pressure again, I would say a wiring problem. But if the fluctuation is between, say, 60 psi and 120 psi, you may just have a severe air leak. For example, a cracked hose to an air bag would result in a major pressure drop, which the compressor would then recover as soon as the pressure drops to the trigger point that turns the compressor back on.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL