2001 Toyota Echo. 212,000 miles.  Automatic Transmission.  Bought car brand new.  Having trouble starting car after fueling (5 gallons all the way to fill-up, and no, I don't top-off). Car starts up and immediately shuts off.  Try to restart immediately and car starts right-up just fine and starts-up just fine until next time fueling.  Then the same problem.  And YES, I changed the Vapor Canister Purge Valve.  The old one later tested Good.  That was my mechanic's first thought too:  Change the purge valve.  He doesn't really know what to check next either.  By any chance, could it be a bad/cracked overfill check valve?  This problem only started after I barely made it home one day (ran EXTREMELY rough and "coughing".  Turned out to be a bad ignition coil and fuel injector on cylinder 3.  Changed all 4 spark plugs too.  Car runs GREAT otherwise and no check engine light or codes.  Any thoughts?  Please help.