General Valve stem seal leak effect on WB02

[Barra]

Would leaky valve stem seals have any adverse effects on tuning and wide band readings? I've had a hard time with a wide discrepancy between 02 reading at cruise vs on boost. I can tune cruise properly but then run lean under boost, or I can get the top end right but then cruise is rich. I don't know if it might be due to the motor pulling oil in when under vacuum creating a rich condition but then keeping the oil out when under boost. Has anyone experienced something similar?

 

[motomattx]

It sounds to me more like you have your deadtimes for your injectors not spot on or your flow settings for your injectors are not what you are actually flowing, it would take quite a bit of oil to move your WB readings enough to care about, I purposely mix a decent amount of oil in with my alcohol and dont really see much richness from it.