Tons of check engine light codes, and it's never run better!

[NovaPath]

So, riddle me this:

 

After doing my valve cover gaskets, i'm getting the following CEL codes:

P1320

P1130

P1141(okay, in full transparency this one was existing).

 

So, I replaced all the plugs with OEM from the aftermarket ones, and also replaced the cylinder 4 coil, as well as some vacuum lines and the pcv valve.

 

The oddest part of all of this, is: this thing now runs freaking amazing. It has tons more power, is way smoother, no more mis firing when starting, and in general the engine runs like new. Why is my emissions check light mad at me for a better running engine now? It runs way better than when I bought it(with no check light on).

 

Not really looking for an answer, I know that it is upset with some sort of resistance reading somewhere, more of a rant