gas leak

I have a 96 328i which had a vacuum leak code that caused the CE light to come on. Replaced the gas cap, which fixed the check engine light. Drove the car maybe about 50 miles. The next time I started it, gas started spewing out (not sure where) but somewhere below the right rear side of the engine. Once I turned the car off it stopped immediately. Kinda affraid to start it back up. Could the gas cap have helped cause this. Any ideas appreciated.