I've been having bad idle AFR's around 13.1 to 14.1 and lean WOT AFR's....so when I installed my j's lower brace i took a look at my headers and this is what i saw!! could that cause bad idle and AFR's?

 

did you ever check the o2? that ^ doesnt look that good lol

 

No not yet i kind of figured that this might be the problem.

 

A leak upstream of the primary o2 sensor can cause mild rich conditions in closed loop situations only as the low pressure waves behind the exhaust pulses pull ambient air into the stream, so the sensor reads excess o2, and the ecu thinks it's running lean and richens up.

As for WOT it's more like SOL. Speed density, which means that sensor is ignored and A/F is all determined from tables.

As to how far it's messing with your wideband, that's the pickle. If both your sensors are falsely reading lean (likely) then you're even richer in closed loop than it says, but not as lean at WOT (though I would guess the offset would be less with more throttle due to higher mean pressures in the exhaust system, so the readings you're getting there might be close to right).