5K breaking up, stalling, leaning out...WTF. Help

[BlackZenkiS14]

So the other day, after the car ran 100% flawless for the past 3.5 years, it finally gave me an issue.

Redtop Sr20 w/ boltons and T28@11psi. Stock injectors.

I was running the shit out of it on some backroads, just having fun, and i had a hiccup around 5k under boost. Turned it off, let it cool, and now it wont rev past 5k hardly.

It will rev fine, make boost, and power fine all the way until 5k, right at 5k it starts stuttering, stalling, breaking up, and making sounds like i'm on my rev limiter. Its not throttle or load dependent. It does this at 20% throttle and it does it at 80% and 100% throttle. No matter what, at 5K the motor goes apeshit. The Air/Fuel ratio goes very lean and becomes very very inconsistent.

I have an Emanage on it, with a good tune. I did not change ANYTHING about car, computer or tune between it working perfect 2 weeks ago, and today.

I have replaced the MAF, didnt fix anything. TPS is fine(reads a consistent accurate signal to my wideband). Injectors are all firing. ECU isnt throwing any codes. It has a newer Z32 fuel filter. New Iridium plugs (1 step colder).

Im assuming its not a spark related issue because it idles perfect, and it goes lean instead of rich.

Does anyone have any advice?