I had the same problem on mine. I got P0172 - Bank 1 too rich. It's the cams that actually stuff up the ECU, causing it to go beyond it's limits for fueling. The base table gets mixed up. Mine was waayyy to tich at idle, but ok-ish at WOT. Spent a couple of hours mapping on roling road, sorted now.

Believe me, it's not a lamda sensor.