P0455,evap system leak (large)

[fixkick]

good, have air. must be carefull not to use too much pressure. even 1/2 PSIis plenty.
there can be other failures , all valves there are suspect. if stick open.
normally the fumes collect in the EVAP tank and can not stink.
my guess is there is a simple breach. (nose told you that)

there are 3 methods,
air, or inert nitrogen.(plus soap spray)
vacuum tests, find it. (soap bubbles not work here, only listening for hiss leaks)
or smoke machine. (see smoke , bingo)
and the horrid way take all parts off car, test each 1 by one, for leaks. (yes, a real pain)

if lucky air pressure applied and a rubber hose held to ear and moved about, all places vent hoses, you may hear that hiss..
can be easy way,,, of all.