Golf V 2.0 TDI 170 – Loss of Power + Flashing Glow Plug Light Despite New Turbo/Waste
 

Hi everyone,
I have a Volkswagen Golf V 2.0 TDI 170 (DSG), model year 2008, and I'm dealing with a very annoying issue that I can't solve.

🔧 The Problem:

The car drives normally when I'm cruising, but as soon as I press hard on the accelerator, especially under load, the glow plug light (flashing) appears on the dashboard, and the car goes into limp mode with a big loss of power.

This usually happens:

• When I accelerate hard
  
• When Sport mode is ON
  
• When A/C is ON
  
• Or at higher speeds around 120–130 km/h
  

Sometimes it happens after 1 km of hard acceleration, sometimes after only 200–300 meters.

🔧 Parts already replaced / modifications made:

• Brand new Turbo (complete unit)
  
• Brand new Wastegate
  
• DPF (FAP) deleted completely (software + physically removed)
  
• Catalytic converter emptied inside
  
• EGR deleted in the software and blocked mechanically
  

Despite all of this, the issue is still exactly the same.

⚠️ Additional Notes:

The problem only appears under load or when the engine is pushed hard.
Driving gently = no issues at all.

❓ My question to the community:

Since Turbo, Wastegate, EGR, DPF, and Catalytic converter are all new or deleted properly, what else could cause this behavior?

What should I check next?

• MAP sensor (boost pressure sensor)?
  
• N75 valve (boost control electrovalve)?
  
• Boost sensor / pressure sensor?
  
• Fuel rail pressure sensor?
  
• Fuel pump not delivering enough pressure under load?
  
• Or maybe a bad software delete of FAP/EGR/CAT causing incorrect boost/fuel values?
  

I’d really appreciate any recommendations before I start replacing sensors blindly.
Thanks a lot 🙏