P0172 ? Need Help

On my way home from work my check engine light came so I scanned my computer and it pulled a po172 System too rich Bank 1. Does anyone know what cylinder this is or what might cause this?? At around 5000rpms the car starts cutting out and also in rolling in first gear between 1000 and 2000 rpms its seems to cut out slightly. I have 42lb inj, 255in tank and t-rex inline pump with a custome dyno tune and about 10,000 miles on engine which until now has been running good. It is vortech supercharger/aftercooled anyone with any ideas???

This may sound weird but, someone told me to check my o2 sensors before the cats, (which I don't have cats anyway) so I took the front two o2's out noticed that they were black which I fiquired may be normal, so I decided to change 1 to the other side to see if the computer picked up the same code on the opposite side of the motor and then I would know it was my o2's. Well I changed them and its been 2 days, the car seems to run better and no code yet ?? What do yall think about that ??