Engine losing power around 3000 rpm

[George90]

Hi there! I'm struggling for 1 week to find the problem on my 01 a4 1.8t ARY, when accelerating around 3000 rpm is jerky and it feels like the engine has no fuel, If I press the acceleration harder it just dies,if I take it gradually seems to be acceptable,but accelerating, starts to boost and around 3000 is dying.
I've changed so far: pcv system, n75,divert valve,maf sensor,spark plugs,and checked the vaccum lines.
On neutral it revs ok.

Did made a scan with a generic obd 2 scan tool,it shows p0036 ho2s bank1 sensor2 and p0136 bank 1 sensor 2,that means is the lambda sensor,but can that one make the car to run so bad? 
help? please.

[Steve Q]

I Wondering if it could be an issue with the turbo or a crack in a turbo pipe? 

Obviously it could also be the lambda sensor as you've suggested.

Cheers

Steve

[George90]

Funny thing is,if I disconnect the n75 seems to work waaay better,and i've just replaced the n75.

[Steve Q]

7 hours ago, George90 said:

Funny thing is,if I disconnect the n75 seems to work waaay better,and i've just replaced the n75.

It's ironic you say that as I had a similar thing with an old Volvo. In my case the mad was replaced. Obviously there's always the chance that it's a faulty maf. Is it genuine Audi?