Car running rich in bank 2...wtf...

[RysRed96GT]

it's headswapped, no tune. CEL came on about 5 days after the headswap with it running rich in bank 2...

...but shouldnt i be running lean? this doesnt make sense to me. could an O2 sensor be going bad? i know i took the one out of bank 1's exhaust and cleaned it some, not 2's. how could it be rich, and how could it be on one side? can anyone help me out here?

 

[2002BLGT]

replace the 02 and go from there

 

[RysRed96GT]

which one? how much are they?

 

[2002BLGT]

front drivers side I think is actually bank 2 on our cars im pretty sure

 

[AquamanCHS]

what was the CEL code?

 

[BlackPony2000]

could be a fouled plug, or wire not all the way in...... buddy had the same prob on his 95 maro..