splutterring

Hi all, Sorry, bit of a newbie, just got a vag-com on my car. It splutters between 2500rpm and 3000rpm, the car has ko3s, stage 2 revo, fmic, full blueflame with race cat! heres what came up 17511 - Oxygen (lambda) Sensor heating B1 S1 Performance too low P1104 -35 - 10 ---...