u/Glittering_Virus_640

Need some ideas before I hand this thing to a Euro performance shop.

Car: 2011 Jetta TDI

6MT

stage 2 deleted/tuned

Symptoms:
Intermittent limp mode with P0234 overboost. It used to only happen during 4th gear pulls or aggressive driving/highway acceleration, but now it can occasionally happen during light throttle cruising in 6th after long drives once the car is fully heat soaked.

What’s weird:
turbo hits requested boost smoothly

no surging/shuddering

actuator tested good with hand vacuum pump and holds vacuum

boost logs were basically matching requested when it went limp

sometimes I can beat on the car for days and nothing happens

other times it’ll happen after getting off the freeway during normal acceleration

What I’ve already done:

replaced N75 twice

checked actuator operation

monitored boost while driving (does not overshoot requested)

vacuum system inspected/ replaced all N75 lines

Other possible clues:

intake/charge piping is pretty dirty

happens only when hot not cold

turbo recently sounds slightly more “fluttery”/staccato than before

At this point I’m wondering:
sticky vanes only when hot?

bad MAF causing incorrect vane control?

MAP/boost sensor issue or wiring?

intermittent vacuum leak?

ECU/wiring issue?

Anyone seen a CJAA do this without obvious boost deviation logs?

I’m so done with this car

I’ve owned this thing for 6 months and I am under the car, crammed into the drivers footwell trying to find blown fuses, or covered in soot with the entire engine bay taken apart every single week.

Here’s most of the problems I’ve had to fix on this thing I’m probably forgetting a few:

ABS sensor
MAP sensor (fucking horrible iykyk)
N75
Nearly Impossible to find vacuum leak
DPF/ EGR delete and tune
MAF sensor
Glo plug relay
EGR pipe (also horrible)
Sunroof
Heated seat
Infotainment shitting itself
Valve cover
Intercooler flush
Ever present airbag light but I’m yet to see a VW without one.

And of course the rare Overboost/ limp mode code i literally cannot figure out.

Not to mention maintenance: every bulb burning out, tires, brakes, fuel filters, fuel additives, messy ass oil changes, motor and transmission mounts, shifter
bushings, window regulator, and the time consuming and tedious process of swapping tunes.

Neither of my two previous 90s Subarus or my 54 year old Chevy have had this many problems and were as difficult to work on as this thing.

This car is in the sweet spot of old enough to have lots of problems and new enough to suck to work on.

By far the most unreliable reliable car I’ve ever owned but it makes turbo noises and sounds like a truck so it’s ok.

Can I reuse the block off plate that’s on the bottom of the pipe and just stick it right on the intake and remove the egr pipe entirely? Or do I need a new pipe.

I bought a short shifter, billet shift bushings, adapter, and weighted shift knob. I definitely need motor mounts and probably a transmission mount.

I’m wondering if super stiff or “upgraded“ motor and transmission mounts will make that big of a difference over OEM replacements.

Should I do OEM motor mounts and an upgraded dog bone? Or all upgraded? Any recommendations?

I’d like the car to have lots of feedback when I’m shifting, but not crazy vibrations.

Thanks guys

Where do yall put the boost gauges on your TDIs?

I’m looking to lower my beloved stage 2 6 speed Jetta and I’d love to see some of y’all’s set ups.

I’m also looking for recommendations on budget short shifter kits as well as any other clean cosmetic mods.

Thanks!