Gas smell when a/c is on

my moms b/f has a 96 ga se 3100. And every once in a while it smells like gas coming out of the vents when the a/c is on. If anyone knows of the problem please let me know something about it advice greatly apprecited. thanks.

Check for a gas leak under the hood. The AC will pull the odor into the passenger compartment. Start the car when cold and look for a leak. I would suspect that it would be somewhere in one of the connectors in the fuel system. Check around the fuel rail. I suspect that you have a leaking o-ring or a loose connection around the fuel pressure regulator.

Also some of the fuel injectors O-rings may be dry rot and leak.