I have a 99 SS with a 402 LS2 with a pretty big cam. It was tuned by a reputable tuner. Now I'm trying to figure out why it's going lean when I go into third (automatic). The injector duty cycle can be seen going from around 65 percent down to about 50 percent and the o2s fall off, but no other sensors I'm logging appear to be changing values to corelate with this change. Therefore I figure it has to be the tuning somewhere in one of the tables that is calling for this leaning out. Any help is greatly appreciated, because I don't want to hurt anything! Thanks, Brian