I recently had a Check Engine Light apper on my 01 lightining. I scanned the code and it reported the left bank was running rich. Has anyone had this problem? If it is running rich on the left bank why wouldn't it run rich on the right side as well? Possible injector problems?

The truck runs great so I am not suspecting the injector(s).

 

it is in the tune. and or plugs. has it been dyno tuned>