loss of power help

[zone]

i had a set of heads put on a couple weeks ago and noticed that the car had been running rich(plugs, valves, and pistons all black) so i bought efilive and when i read my current tune my previous tuner had set my pe vs rmp from 3600rpm and up 10.8afr so i leaned it to 12.2 but the problem is that it slowed the car down and was not getting anymore kr so does anyone know why i would be loosing power with the car leaned(but probably still to rich)i switched between my old tune and the new(only thing changed was the pe) at the track and mph was down w the new tune, also my o2's are reading 930mv with the old tune and 880mv with the new tune i put on, but like i said it seemed it was making more power rich, also i made multiple runs both ways but the car seems like it is running slower than it should both ways best on motor was 12.1 and nitrous 10.9 at 125 any help would be appreciated


cam is 222/228 566/571 113lsa
heads are ported ls6
4l60e trans
255lph pump
ls6 intake

[dfe1]

Keep in mind that the PE AFRs are COMMANDED, not ACTUAL. You're going to need a wide band to correct the problem. My guess is that you won't see anything close to 10.8:1 with your old tune. Actual AFR will probably be pretty close to an ideal setting, and when you command 12.2:1, the actual AFR is too lean. Forget narrow band readings at WOT or any other time you're in PE. I've seen a full ratio change make a difference of less than 40 millivolts in narrow band O2 voltage.

[Doc]

What kind of vehicle is this? I have the relatively same set up in a 98 Z. You have to have a wideband. You have come this far. 150 and no more witch doctor, Miss Clio BS. Do it.

[zone]

2002 trans am, i think i was going from too rich to too lean, i'm taking it to the dyno jun 3 so i guess i will see