Help! Chasing the P0011, P0300, P0340 Codes!
 

I know I've seen this issue pop up many times, and I can't seem to find a definite solution. I have a 2012 with a little over 135k miles. I initially started noticing a vibration when I was coming from a dead stop in first, and I thought my clutch was finally going out. Started getting the P0300 and P0340 codes, which I thought could be caused by the vibration making the computer think it was misfiring. Also started getting P0011 and the car began going into limp mode. Wouldn't rev past 3500, and occasionally the TCS light would come on and SyncRev would cut off. And finally, now it sometimes won't start at all. It acts like the battery is dead, and I'm having to jump it off. I have a known issue with a disconnected 02 sensor, but it's the downstream bank 2, and I don't see why that would cause the limp mode and these codes.

So here is what I've tried so far:
Checked voltage to passenger side cam sensor(P0340)
Cleaned grounds closest to cam sensors
Replaced both cam position sensors
Swapped cam sensors from one side to the other
Replaced VVT solenoid on that side
Replaced crankshaft position sensor
Checked oil pressure
Reflashed my Ecutek tune

My oil did get low because I was a little past my normal oil change, but I don't think it was low enough to be detrimental. I think I read someone's issue with multiple sensor codes was a bad battery, but I'm not sure that would be the issue here. Any suggestions before I start ripping into the front of the motor??? My next thing would be the cam sprocket. But once I'm in there, I'll probably change the gallery gaskets, tensioners, guides, and water pump. Just really hope I'm missing something simple.

Update: I replaced my battery, and that fixed the no start issue. I'm not sure if something caused the battery to die or if the timing just coincided with my other issues. Code P0340 is still coming back, but P0011 and P0300 have not yet come up again. The car is still going into limp mode periodically.