May not be relevant but the ground on the O2 sensor gives problems on these so worth a check. Noise on scope images is usually interference from earthing to battery or vehicle, try a floating earth to O2 sensor and also try activating filter option in drop down menu (channel options). The use of the M1007 passive high impedance probe gives better results than the standard lead supplied. Pico supply the lead if you didn't get them in your kit.

Mark