2004 GMC Sierra 4.8 Knock Sensor and O2 Sensor Codes

[c3xauto]

I have a 2004 GMC Sierra with 4.8 L. The truck loses power when you try and kick it down, but does okay under light driving. It is trowing codes P0332 (knock sensor), P0131, and P0151 (both O2 sensors). The O2 codes are pending. Does anyone know of anything that would cause this combination. I could be the fuel pump, knock sensors, cat, but I hope not!

thanks

[c3xauto]

I found out that it is actually the gas gauge. The gauge is reading 1/4 tank when it is actually running out. P0131 an P0151 are lean codes. The knock sensor code was actually a bad knock sensor, but it didn't affect performance.