ep409

I dunno if that might help, that was at idle
I had recently changed the 02 sensors on my truck, and I redid my exhaust to dual 3", it's a 4x4 with a 5.3 and a 220r it is tuned for it. well it worked fine for like 2 days then yesterday it started smelling like its running rich and when i let off the throttle it shudders, doesn't seem to be idling right either. I just replaced the wires and plugs when I changed the 02 sensors jist looking for ideas on what maybe wrong. Could it be the MAF? Or maybe the tune with the new 02 sensors it had denso ones I bought new denso ones.