Are you going by commanded and actual AFR with a wideband?

Setting commanded AFR to 11 is easy and fuel trims will not pull that much fueling if any at WOT with these dumb pcm's.

Perhaps you have a real fueling problem, like a failing pump or clogged fuel filter if you are commanding 11.0 but are seeing over 12 on the wideband. Watching injector duty cycle is anything to watch, you could be maxing them.