Rick.Cook23@yahoo.com

I've been working on 1.8t motors (Audi and VW) for years now, but I've had a probably of late that I cannot figure out.
Hoping someone here can enlighten me. Car is 2000 A4 with 1.8t, 5sp.
I use it for track-use only so it has no behind-cat O2 sensor, a straight exhaust (2.5inch), with APR stage 1 tune.
Turbo is stock K03, airbox is stock, stock side mount intercooler, engine is stock.

Problem is that the car sputters at wide open throttle (WOT). No codes, no CEL.
I have replaced all of the following (all with stock parts) over the course of a year and various track/race days:
- plugs (yes, gap is correct)
- front O2 sensor
- Fuel injectors (not sure I needed to do that, but it was getting time anyhow)
- Fuel pump
- Fuel filter
- MAF, IAT, MAP, Coolant temp sensor
I have VAG-COM, and log anything that we need - I just don't know where else to look?
- Boost is good (about 15psi, spiking at 18-19psi)
- engine temp is good (80-85C)
- intake air temp is good (what should amount of air be - g/s? what to log to see that?)
- Fuel pressure is good (is there something I can log to see how the new injectors are doing)

Running out of ideas - so any help will be appreciated. Even if it's just a "did you check/try this?"
Thanks.

Rick.Cook23@yahoo.com

As a bit more info...
This is measuring block 115 - from a 2nd gear pull (can't do much more on my neighborhood streets), showing:
RPM, engine load?, requested boost from ECM, and actual boost measured from MAP.
Note that RPM is 4400 - right in the sweet spot of max boost, and torque, for these 1.8t motors.
This is where I'm having the sputtering problem.

Actual boost (purple) is a tracking requested boost (yellow) fairly well, but actual boost does go a bit higher (2200mbar vs. 2100 mbar).
Could I possibly be going lean here?

Also, it's now in the graph, but in the data view below the graph, the second variable in group 155 - engine load - what is that?
What does it measure? And why would load ever be more than 100% - mine shows 146%???

Again, thanks for any help.