As far as I know, this is a stock setup.

I run in to this issue almost every time I give it significant throttle, and under heavy boost. If it will help, I can take an in car video of it while it is happening.

It seems as if it is a misfire, but there are also some leaks in the catalytic converter under the hood. I ran a diagnostics and no misfires were indicated by the ECM.

How do I determine what the cause of the misfire is? It almost sounds like a 'popping" when you hit a rpm limiter, but it is nowhere close to the rpm limit when it happens.

Could it be the Catalytic converter causing the misfire?

 

check you plug gap, you could be getting blow out, or your cat could be starting to get clogged.

 

I have to get a new Cat regardless, what would you guys recommend for a direct fit, and high performance? I do envision putting a new stainless high flow exhaust on from the cat back after I replace this cat.

What options would i have as a step one (replace leaky/faulty cat), or maybe a complete change out right now?

 

You can get direct fit high flow cats from 034 if you're on the west coast or RAI if you're on the east coast. Both do excellent work, but they're not cheap. If you can get away with not having a cat at all, it would be cheaper to get a cat delete pipe a.k.a. "test pipe." Both will fit in the stock location.

 

i have the same problem! I cant figure it out either. mine also occurs if say im cruising in 5th or 6th, then downshift to 5th or 4th and start to accelerate, it will what feels like a misfire. no codes either. I have had this problem since i got the car, I have changed plugs, injectors(stage +2 APR) catless exhaust.

only thing i can think of thats left is a coilpack issue. so maybe if the OP has same issue then could also be a coilpack.

 

As soon as I go over 10lbs boost in it seems to occur. Say I am chugging along I. 4th, snack the throttle and it builds over ten, it starts to happen. The blow through almost sounds right.

 

that's definitely, spark blow out/ weak spark. start by checking your plugs/ plug gap, if that doesn't fix it, start looking at coil packs.

 

I have an update. I threw some new plugs in. I went with NGK Copper's as copper is recommended with these and it is a little bit better but still happening.

I took a highway trip and in safe areas spooled it up good and long to get it to hopefully record some codes.

I hooked up my code reader and got (loosely quoted) "Misfire Detected on Cylinder 1" x2 and a Ignition System Code to go with it reading weird fuel/air which at this point I assume is from un-burned gas dumping in to the cat.

I assume I need a new IC there. Will update after the new IC goes in!

 

4 new coil packs, and she is gold!

 

Good to hear, did you get the updated version?