Originally Posted by ZXthrizzle05
pretty sure theres a vac leak somewhere
That does sound right, it really doesn't resemble a totally dead cylinder at idle and in the video, the car seems to run fine with some revs and once you get into any boost which would basically negate any vacuum leak idle problems due to the proportionally way smaller air intake volume at idle, it also disproves any doubts about ignition because it seems to be running well with more combustion pressure at speed and when boosting. When you're boosting does it feel down on power any? Does the AFR stabilize more if you're cruising steady speed with some boost present? If the AFR is stablizing under more engine load, in theory that directly points to a vacuum/boost leak.
Neither you or MotherFocus have directly stated that this is a recently built engine, if that's the case it might just be a matter of some intake piping that popped a little loose somewhere.
I don't have any firsthand FI experience, surely Tom and others here could validate or disprove that it's a vacuum/boost leak.