Unexplained Power Loss

[Rogerbslee]

I’m new to the forum and have a 2013 Jetta Tdi with Stage 2 Malone tune and 75k miles.
Car runs great some of the time. Very responsive and pulls hard specially in low to mid range where I like it most. The rest of the time (and especially once fully warmed up) it’s very sluggish. Feels like a severe lack of boost.
No trouble codes. VCDS shows actual boost lags specified boost but I’m not sure how well they’re supposed to match up. N75 output test and actuator operation seem normal.
Replaced N75 and MAF sensor just in case. No luck.
What’s left? Sticking VNT vanes when turbo is hot?
It’s driving me so nuts I’m close to replacing the turbo just because I can’t think of anything else.
Has anyone experienced something similar and found a fix?
Any advice appreciated.
Thanks

 

[CanadianALH]

Take the tune off and see if you have the same issues without the tune, if you do then it’s something hardware related. If you don’t have the flashzilla you can email them and ask them to send you a rental and that you need it to trouble shoot a problem they will likely send it sans rental fee and you just pay shipping

 

[Rogerbslee]

Take the tune off and see if you have the same issues without the tune, if you do then it’s something hardware related. If you don’t have the flashzilla you can email them and ask them to send you a rental and that you need it to trouble shoot a problem they will likely send it sans rental fee and you just pay shipping

I should have said but that was one of the first things I tried to no avail. I feel pretty sure it’s a hardware issue and does seem to be temperature related. The only similar complaints I’ve seen from other owners involved sticking actuators or turbo vanes and one case of a blocked catalytic converter. I’m afraid of making a costly mistake if it doesn’t fix the problem but I think I’m ready to take the risk and try a new turbo if I can’t come up with any other ideas