What could cause O2 variation from bank to bank

[knguyen]

When I do a FATS run and log I notice that at about 4000 rpm WOT my bank 1 is about .04-.05 volts higher than bank 2. If I add fuel via lemmi they both increase, but are still off by one another.

First I replaced my o2s and they are still the same.

Then I used a wideband on one side and then the other. The wideband says there are off by about .5 to 1.0.

Then I thought it was a clogged injector so I swapped pairs of injectors relogged after each swap. No change.

Any other ideas? Running out. Someone said timing may be off a tooth. Wouldn't I have a lot bigger problems then just AFR.

The car seems strong. Runs smooth. Idles smooth. Misfire codes, but that is "normal" for stage 3 with test pipes. No lemmi tweaks. No unusally high CFs (9) or knock values (~35 max). The car dynoed strong on a mustang dyno in the mid 400 hp/tq where a stock s4 makes 197 hp/ 220 tq.

[The_Jerbel]

Could be your EGT sensors.