Injectors are 265cc and stock turbo (k03-015)
But in bfb engine boost does not raise fuelpressure so if it have 4 bar and you get 1.5 bar boost real fuelpressure is only 2.5bar, maybe this is the reason.
Good afternoon.
After searching the web for about 2 months I found your problem which is exactly the same with mine.
2 months ago i bought a used A4 B7 AVANT (8ED) QUATTRO (2005) 1.8T BFB (120kw), which is the logical next step from my previous car which was an A3 8L 1.8T AUM (REVO STAGE 1) (sold with 277.000 km and the 150.000 after tuning)
After upgrading to stage 1 I had the same problems as you in 4,5,6 gear whenever I push the throttle a little more faster than slowly (things start to go bad when turbo pressure builds up).
I have changed a fuel pump , CAT, MAF, cleaned and tested the 270cc injectors, PCV valves, plugs, 2 fuel filters (1 6 bars and 1 original Audi at 4 bars) at a cost of almost 1000 euro.
My pressure is OK and my lambda is OK.
The car is improved somehow (since everything is new), but I still have the problem.
My fuel injectors stay open 25-30 ms in order to deliver the fuel which obviously is not enough.
The tuner said that the car should have delivered 190-200 hp with stock injectors, which obviously is not happening in my case when on 4,5,6 gear and especially when the the road is climbing
How did you solve the problem?
Did use 310 or 380 cc injectors?
If yes did you change the tuning?
I will be more than thankful if you could help.
By the way are you Greek like me?
Thanks in advance.