I have a 98 malibu 3.1L V6. After I have the gas tank filled and restart the engine, it surges wildly. The tach needle swings up and down. It doesn't stop till I gun it and get going and drive for a few minutes. Then it's OK till the next refill. I also hear a loud bump sometimes when stopped and idling coming from the rear of the car. The check engine light is on as well. I know there is a purge valve and a vent valve. Could the fuel pump be pulling fuel out of the tank and causing it to collapse a bit from the suction if it's not venting?
Thanks
Mike S

Welcome to AF, get the code and also have the fuel pressure tested.