turbo? Knock sensor? running lean?

[ddouglas77]

Originally Posted by SideWinderGX

knock is the preignition of gasses in a cylinder. it happens if you ahve too high of an octane in your car, or if you mix them.

although, i dont think mixing gas matters as long as its the same octane. maybe it was a bad batch from one station that messed up yoru entire system.

um, if the blow off valve is leaking, thats obvoiusly not a good thing, although im not sure how that would relate to knock or anything messing up.

No, preignition happens if your octane level is too low, not high. The higher the octane, the cooler the burn, which is why it is only supposed to be used for boosted, nitro or high compression engines.
The BOV leaking under vacuum will more than likely leak under boost, which will cause a lean condition.