Two codes are on need help please!

[fast enough Z28]

I've got code p1133 and p0507 showing up. The exhaust is leaking a little where the stock header and cat bolt up. Is that the problem or is it the o2 sensor. Thanks for all the help!

[0rion]

p0507 is Idle Control System RPM Higher Than Expected. Have you worked on the car recently or messed around with the throttle body at all? I would try cleaning the tb and checking for vacuum leaks.
p1133 is an insufficient switching code. This is sorta common with longtube headers but your post makes me think you're still on stock manifolds. If on stock manifolds I would switch that sensor to the passenger side and see if the code follows it. It would throw p1153. If that code throws then I would replace the sensor.

[fast enough Z28]

I still have the stock manifolds. A couple of days ago I took the cat and manifold off, I wanted to put a copper gasket between the manifold and cat but couldn't find one.

[mrr23]

check the rubber hose that hooks to the intake and PCV valve. it has a habit of rotting on the bottom side of it. the hose is about 2" long.