I've been running around tuning both on the street as well as some dyno time lately. I've been tuning in open look to get MAF tables and all that dialed in where they should be. I'm .98-1.02 lambda at idle per the wideband controller in open loop. When I re-enable closed loop, my short term fuel trims are -17% for bank 1 and -7% bank 2 at idle pretty consistently. My wideband is in bank 2. Do I need to add a negative voltage offset in the B1 and B2 sensors to get this to align better? I've had this problem for as long as I've been tuning with a wideband. Something has to be wrong. I've swapped the O2 sensors side to side and also replaced them with new ones within the last year. I'm running E85 and have stoic set to 9.8 in the tune.
2007 Mustang GT listed in my signature.