1997 Pontiac Grand Prix car shuts off

My car hesitates at the initial start up. If it starts. And while diving, it frequently shuts of when I let off the accelerator, or come to a stop, but starts right back up. If it sits for awhile it while start right up as well. I thought it was a fuel problem so I changed the fuel filter. I also hooked up to the obd2 port and it read codes for mass air flow and vaf sensor. I checked for any vac leaks and noticed a couple small warps on the upper intake (which is plastic) and wondered if that could be it. Do you know if this is a common prob with pontiacs? And what would be the ideal way to check for a leak in that area?