Remanufactured 5.3 engine not firing on one bank

Check the battery, maybe some cables which should be connected to the sparkplugs aren't. Check the alternator, maybe it is not restoring enough power for both banks. A friend of mine had the same problem. He checked the sparkplugs and one bank had no power, because of loose cables. But please do not try to drive! Your issue could badly affect the crankshaft and the conrods of the second bank.

This post is old but today I was called out to a truck with the same problem. It turned out that one of the coils had shorted out and blew the fuse for the left bank. I replaced the coil and replaced the fuse and all the cylinders were firing again. The fuse was a 15 amp under the hood and labeled *2 with a note to check the manual as to it's purpose. Next to it was another labeled *1 and I would guess that to be the other bank. Hope this helps.