Appreciate all the help.  Since my RV is in storage without the ability to hook up to shore power, I will have to wait to replace the GFCI.  I will double check the outlet inside the storage bay and the outside outlet (it has a cover).  I guess I could also go get the percolator and bring it back to the house to check it out on a GFCI outlet here; however, I have also used the crockpot and rice cooker.  The results were the same.  Sometimes it continues working for many days in a row without a problem and then the next time I will try to use it, the GFCI has popped.