Audi A3 1.8T (8L) turbo suddently cuts off at around 3000rpm.

When accelerating the turbo suddendly cuts off at around 3000rpm, sort of a lag that is only one second long cause then it imidiatly comes back. It doesn't happen all the time, when driving around town slowly it will not happen, most of the time it happes when accelerating hard, most of the time in second gear, less in 3er gear. It never happens on 1st gear.

My turbo, and the intercooler were clean some weeks ago trying to solve the problem but nothing. I have had this problem for over a year, it comes and goes and doesn't gets better nor worst. I install a forge hybrid bv a couple of months ago. So when the power cuts of I can hear the valve "wuuush". For the second that the power cuts off, I can also hear that the turbo stops spinning for that second.

No one knows what the problem is, cause there is No check engine light on. Hope I can find some help with you guys.

Thanks for your attention and your time.