Quote Originally Posted by oj88 View Post
Does the TS detect a whoosh of rushing air whenever he opens up the fuel cap? The problem could also be caused by too much vacuum in the tank.

For emissions purposes, the fuel tank is maintained at a slight vacuum to prevent it from venting unburned fuel into the atmosphere. If the vacuum is strong enough, it could cause the tank to buckle.
I do experienced that, whenever I do refills I could hear air escaping.

There's also this weird thing: Usually I stay inside the car at the parking lot in the morning because I usually comes in too early. After 5-10 minutes I would hear a huge tug or was a huge popping sound underneath the car and it could be the gas tank?

*1997
Do you experience this loud "tog" sound underneath? If not try to stay inside the car after you drive it. The sound usually comes in after 5-10 minutes. I guess its the air pressure being relieve and it flexes the gas tank to original position.