4.3 engine swap part two

Changed a 1998 4.3 vortec to a 2002 4.3 vortec. It starts and runs for a minute fine after i turn the key to the on position and wait about 30 seconds then start it, then it chugs and dies. Can not give it gas, it chugs. Changed filter. I'm guessing fuel pump? I still find amazing that my fuel pump would go out at the same time i switch the engine, but so is life.

yep, sounds like fuel pump, did the vehicle sit for very long for this engine swap, was the tank empy?

Just bought truck guessing it sat awhile. Changed oil. Drove about 50 miles before found water in oil. Fuel pump worked fine. Guessing tank didn't have much gas when it sat. Had a quarter tank when i bought it. Switched engine now some saying 2002 to 1998 won't work without the 2002 computers. Waiting for new fuel pump to see if thats it.

The computer should be easy enough to check just by calling a GM dealer. If you have the number off of your computer (part number), you can usually google it and come up with sites that will tell you what vehicles/years that number spans.