need some help guys

[Mr.Soup]

Took my O1 cobra to the track a month ago for the first time. Mph was pretty low so I brought her home. A while back I installed a catch can system, I discovered it was clogged up pressurizing my crank case so all of my spark plug tunnels were full of oil.
This past weekend I replaced all my plugs, installed new pcv valves, I had a K&N filter on the end of my mass air meter but relocated it to inside my fender well, Yanked off my iac restrictor plate and swapped my slp lm1 catback for a Mac.
I took her for a drive yesterday and it seems to accelerate well but cruising at a steady speed it has a stumble to it. My check engine light came on. I ran to oreillys and pulled codes p1O7O and p1O74 banks 1 and 2 lean.
Came home with a can of mass air cleaner, cleaned it and checked for vacuum leaks, there are none.
Does anyone have a suggestion as to what should be checked next?

 

[Nightmare90gt]

O2 sensors bad maybe. So sounds like you need to replace your valve cover gaskets

 

[01yellercobra]

It's rare that both sensors go bad. Usually if there's codes for both banks it's a vacuum leak or MAF issue. Double check around the MAF for leaks. Someone on here had issues with the adapter flange not being the same size and causing a leak.

 

[Mr.Soup]

I'm wondering if I roached my O2 sensors, when yanking my old plugs all the oil that v was in the channels ran into the cylinders. When I started it up she smoked like crazy for 5 minutes.