Gas Dryer suddenly trips any GFCI Outlet immediately upon being plugged in, but works fine in non GFCI
Same problem here: plugging in gas dryer, with dryer off, immediately trips GFCI.  GFCI is new;  dryer is old. I doubt the "fluctuating current" argument:  a washer, with its different cycle starts/stops, is going to generate more "fluctuating current" events than a gas dryer. (Also the dryer is off when I plug it in.)  I thoroughly cleaned the inside of the dryer, removing all lint, and brushing dust off of all components.  Still trips when plugged in.  So I disconnected/isolated hot in the dryer's control panel:  still tripped when plugged in. Then I also disconnected/isolated neutral in the dryer control panel: still tripped! New test:  without the dryer, ran a test lead from ground in the outlet to the gas pipe connection: trip!  Measured a small AC voltage (30mV) between outlet ground and gas pipe. Next step (in this case) is to talk to some people about grounding requirements for gas supply pipes.