Torque drops too much e46 2.2i

Hello, I hope I posted in the right section.

Having more time to spend driving, I noticed something bad going on. Car lost its punch at low revs(up to 3k rpm) and around 4200 rpm looses torque very fast, like an air gap, for a fraction of a second, then continues accelerating.

So I went to a dyno to see the graphics. The guy there told me the AFR(air to fuel mixture) is too high(too little fuel) and it should be under 12. In the 3rd run, he tested the car in 4th gear, the others were in 3rd.

Monday I am going to a tester to see if there are any fault codes. I have no "check engine" on the dashboard, no warnings.

What could cause the torque drop? Could be the Vanos system? The engine doesnt rattle, no weird noises, nothing.

Have you checked/replaced the DISA ?

Where is DISA valve situated? And how can I check it?

eventually a realoem code

Found it. You think it could be it? Because there isnt any rattle ...

Looks like a normal power curve to me. How is the MAF? Running an intake? Do you have any vacuum leaks? And when is the last time the car was serviced?

Well, it needs its service done. I mean, oil and filters. But I'm concerned about the torque drop which happens always at the same rpm. If it was to be filters, wouldnt accelerate badly after an rpm point? Mine hesitates at 4200 and after, it continues to accelerate well.

The engine is stock, no modified intake. About vacuum leaks .. I dont think so, I think they are good.

vanos seals perhaps?

I have the same problem, around 3000+ rpm, always in third gear.

I've checked camshaft sensors, DISA and had codes read... nothing.
I had a battery replaced and the issue seemed to go away, only for a day or so :\

as mentioned, Check/Clean the MAF

Also been done, as well as vanos seals. let me know how you go (op)

Knock sensor becoming old, and pickup up excess noise, and could cut back the timing and kill power, or pre cat O2 sensors could be old, or or or or. You really need to have some sort of scan tool hooked up to the sensors to see what the problem could be. Also check to see if the DISA is leaking or rattling.