2008 tahoe 5.3l in need of desperate help

[Nickct203]

At my buddy's now, the dod kit has a module that plugs into the obd port. It runs a little better when it's plugged in but still sounds and run rough as hell. The misfire codes went away but now it has a p1600. I'm about to give up on this truck.

Oo the valley cover also helped little but still helped atleast