Gonzaga

Don't put atmo blow off valve to 1.8T, it's designed to work in closed loop. If you want to keep position of DV as it is now, just reverse it or put it on TIP like it is now installed.

Your OEM DV is connected in reverse, it should be rotated by 90 degrees

Bad fuel pump

Authorized Skoda/VW dealer have a fuel pressure tester. Measure it and post back the results. Also pressure test the boost system for leaks. Do you have a boost gauge?

Three type of 1.8T engines where in mk1: AGU - 150hp K03 non-DBW -> stage 1 cca 170hp AUM - 150hp K03s DBW -> stage 1 cca 205hp AUQ - 180hp K03s DBW -> stage 1 cca 205hp

Log MB 015&016, misfire counter, via vagcom. Value should be in all blocks 0 or 1, if its start to rise usually coil pack/packs are on its way out. Testing should be done in 3rd or higher gear, from 2000rpm and up.

Yes it is, s3 uses the same wideband lambda sensor but also has EGT sensor which octavia doesn`t have.When egt starts to rise ECU dumps more fuel to cool down the motor.

Yes they need mapping,use stock rail and 3 bar fpr. No need for 4 bar fpr, if you need more flow than s3 injectors can provide it`s better to use 440cc green tops.

TT and S3 injectors are the same, injection time doesn`t go over 20ms or 80% IDC, that`s why they are better.

I do

You say DV (spring stiffness) is the problem, can you tell how much boost you have @3500rpm and @5500rpm? Wouldn`t be logical to presume that DV is not the problem, if it can hold 1.2bar@3500rpm but can`t hold 0.7bar@5500rpm? Maybe I`m wrong

Sytec p3031.1 fuel pump, it`s a good upgrade. You should log block 031 and see what is going on with AFR, I bet it`s leaning out at higher rpms, also causing boost fluctuation.

How old is the car? 10-12 years? I bet it`s a fuel pump Flat line after 5000 to a red line indicates fuel issues, clogged injectors or/and failing fuel pump. Buy this: http://www.motorsport-tools.com/sytec-hi-in-tank-fuel-injection-pump-36mm-in-8mm-out-p30311.html

Landi Renzo Omegas system

6 years on LPG with no problem, 1.8T Stage 2 (225hp, 372Nm).