i have a 1994 bonneville 3800 motor that runs grate but stalls when slowing down

i have a 1994 pontiac bonneville with a 3800 motor that runs grate but when you are going slow usually with foot off gas or slowing down or when coming off highway it stalls? when i put it in neutral it starts up and runs fine the survice engine light comes on for a little while than goes out the code scan says its the EGR valve could this be right? Help its getting scary.