On Sun, 10 Aug 2014 13:45:19 -0700, "Howard Beal"
wrote:

Car is a 2003 mercury sable GS, V6 engine.

Fuel is leaking from the top of the gas tank only when the
engine is running. With the key in the run position i can
hear the fuel pump turn on and pressurize the system
and there are no leaks. It only leaks when the engine is
running. The fuel pressure is within specs. Only 50k
miles. New fuel filter installed. Using shell regular unleaded gas.
No OBD codes when scanned. Check engine light is off.


Any idea why it only leaks when the engine is running?

Many EFI systems use a fuel return line to route excess fuel from the
pump back to the tank. You probably have a bad line at the tank,
where it switches from steel/copper to rubber to mate with the tank.

I suggest dropping the tank and replacing all lines there, as well as
any other fuel line rubber on the vehicle.



--
Aim for success, not perfection. Never give up your right
to be wrong, because then you will lose the ability to
learn new things and move forward with your life.
-- Dr. David M. Burns