Cutting out/studdering at 3k-4k

[4g63tcrazy]

So I can't figure this out.. When driving the car and giving it some throttle to get the turbo spooling, the car will studder really bad, wideband goes full rich, and I get anywhere from 10-15 counts of knock. It happens anytime I'm over 25% throttle. It will also do it just when I free-rev the car. At the same RPM. It does it right at 3k to 4.5k and after that it rev's smooth all the way to 8k.

I have tried adding a bunch of fuel, taking away a bunch of fuel. Taking away timing and zero'ing everything out. Nothing made any difference.

I swapped the CAS 180* out and car still free-revv'd the exact same.

I put the CAS back, installed new spark plugs. Gapped them at .24 and changed nothing.

Did a boost leak test. My BOV gasket leaked slightly and the throttle body leaked slightly. Fixed both of those. Didn't change a thing still.

It feels just like the car is misfiring when it does it. EXACTLY like a misfire. Then it just goes away and rev's fine to 8k. What am I missing? I feel like I've checked everything..

I would attach a log I did of when it happened but it says invalid file..