Thanks, Mike P...30_40 also had a interesting tip with the non-vented gas cap. I'm suspecting that your right about the cooler temperature of "fresh" gas allows more fuel to be added than should be...however, the second time excess pressure built up, the car had been sitting in the garage for two days before starting to spew out the relief line which is located just above the filler tube. I had driven the car for approximately 10 miles prior to parking it so I know there was "some" amount of air space inside the tank. I also tried a non-vented gas cap but the pressure came out the vent tube along with a small amount of gas so I drilled the cap and installed a small tube which routes thru a drain tube at the bottom of the gas cap area. since then, about 1 week, there has been no pressure. Have my fingers crossed on this on...Thanks to all the Forum members for the suggestions and advise.