I hear a "metal popping" as I exit my Buick after shutting off the engine. The metal popping noise is the same noise the old one gallon paint cans make when the temperature changes. Any suggestions? I am thinking the fuel vacuum canister is leaking but it is plastic.
Also my "Check gas cap" flashes in the DIC. I replaced the gas cap with an Autozone cap and replaced the 3/8" main steel fuel pipe-filter along with the two steel 5/16" recovery fuel line and canister pipe. The check gas cap came first before the popping noise.
I agree, sounds like the vent solenoid might me stuck shut causing excessive vacuum in the tank. There is a pressure sensor in the tank that monitors whats going on, usually it sets a code because there is a leak and it can't build any vacuum, sounds like you have the opposite problem and have too much vacuum.
There is no build up of vacuum in the fuel tank. Also, I forgot to mention the "Check Engine Light" is illuminated. The light cleared up once but is back. The code is something like A404, not sure on the code.