Engine cranks, starts, but will not stay running?

Van was running perfect. I owned it for 3 days. It began to make a surging noise and lose power. The engine wanted to accelerate but could not. Almost like driving with the E-brake on. I went to make a 3-point turn and the van stalled in reverse. Couldn't start for about 30 minutes. I was able to drive it about 1/2 a mile. It stalled again. I've been unable to drive it since. No check engine light, all gauges remained normal, except the battery gauge began to jump around. As of right now, the engine turns over and even starts, but shuts off immediately after I release the key. The transmission is rebuilt and has a new fuel pump.