Missfire and bad gas smell

[That_z71_]

Hey guys, I own a 2004 Chevy Silverado z71 5.3l, just recently put another 5.3 in last one had water damage and snapped rod, the 5.3l I put in was doing fine for about a week then it started to rough idle so I replaced the knock sensors and that didn’t work so I replaced all 4 o2 sensors and that didn’t work, so I quit worrying about it for a few days then I had a bunch of low voltage codes for knock sensors and o2 sensors, random multiple cylinder misfire and evap codes and also system running too lean, so I put new spark plugs in and also took the coil packs and spark plugs wires off the old 5.3 and put on the 5.3 in my truck and still no luck, so at the moment my truck misses and smells like raw gas out the exhaust, I also put a new fuel pump in recently, would any of this have to do with a bad ground wires somewhere since it’s nothing but a bunch of low voltage codes?