Fuel pump. There are two. The main behind the driver and the 2nd on the right side.
There are quite a few threads on the topic.
Each pump has it's own fuse located here
You can figure out which pump is weak by pulling the fuse and letting the other kick on. - both pumps run on startup. If the main is bad, and you pull that fuse the 2nd will continue, keeping the engine running. (full throttle needs both pumps)