I;ve had "16556 bank1, fuel measuring system to rich" appear twice in the plast 3 weeks, frist time the garrage cleared it and it took 3 weeks to come back up. They have no idea what could cause this, I've read that it could be an O2 sensor failure or intermitent fault.
I had a new MAF fitted a few weeks ago so I doubt it's that playing up. any ideas?