1.6 hdi rough idle when cold with P0104 and P0113 codes

[Bizsi05]

Hi!
I am having issues with my 2007 C4 gp 1.6hd 9hz. It has 120k km on the clock.
About a month ago I replaced the injector return line, because it was cracked, and was spilling diesel all over the place in the engine bay. The car worked just fine for about two weeks I parked it one night, and the next morning the engine at idle would shake like crazy, and when driving the car around 1200-1800rpm the engine shakes the whole frame of the car. It also has reduced power, and the exhaust gases smell bad, it never smelt bad before. The engine shaking disappears when it gets to operaring temperature, but it still smells bad, and has less power.
I tried to chase the problem with diagbox. It shows me the error codes: P0104 and P0113. It would seem like the MAF unit is bad, but the measured values are correct. (Both airflow and temperature) I tried replacing the MAF unit, but the issue remained the same.
Next up I checked the EGR valve, but it opens and closes just fine, it strictly repeats ECU commands.
The fuel rail pressure is also fine at idle around 200bars, and goes up as i rev the engine to more than 300 bars.
I cleaned the intake pressure and temperature sensor after the turbo.
At this point I am out of ideas, did anyone have the same problem before, and found a working solution?
The only thing that I am noticing, is that the hand priming pump for the fuel on top of the intake shrinks when the engine is on, like its under some vacuum, but I dont know if its normal or not.
Thanks!