stalling issue
 

Hi all. I have a 2008 aspen, 5.7 with 228,000 miles on it. I recently had the fuel pump replaced ( last week) due to it cranking, but the engine not starting. When I drove it home from the shop I hit a decent sized pothole, which seemed to trigger the car to stall. I pulled to the side, turned the key off, then turned it back on, and the engine started right back up. I took it back to my mech, but after road testing it for 80 miles, he couldnt make it stall again, and chalked it up to an air bubble in the gas line from the new pump being put in. While driving to work this morning, I hit another pothole ( its NoVa, so yeah our roads can be a bit sucky), which again triggered a stall. I again pulled to a stop, (luckily no one was behind me), turned off the key and turned it back on, and again the engine started right up, and it drove fine the rest of the way to work. My question is, wtf is causing the stalling, and what can be done about it? thanks in advance.