Strangest thing I ever saw. Does it at start up no other time. NO CEL.

 

That is weird, p1313 is grouped in with miss fire and cat codes and is supposed to turn the CEL on immediately.

 

1313 is for the multiple misfire at cat damaging level, and part of that detection is a change in engine load. So maybe plugs, or maybe AC compressor about to cause grief? Dirty IACV? Does it throw it when AC selected while driving (not at idle)? See attached.