i had simmilar prob but different code 18075 along it ended up being the wiring loom on one of my injectors, i had changed maf and got rid of egr b4 buying reader but as you hav the code and tried several things i can only add what happened to me.
it cost £130 for vw to change loom now all good
not sure if any help but i found any idea helped when it went into limp mode
just read your other thread and i pretty sure thiss comment or info wont helf if it was about the turbo.
good luck though