Serious Issue?

[TheExile]

Hi all, so my partners 2016 VW Caddy Maxi Life 2.0 TDI auto hit a serious issue about 2 months ago, whilst driving along the engine suddenly went and she rolled to a stop (at the time she said there was a "clonk" but im now not sure if she meant like a bang or just a funny... the AA diagnosed it as a fuel issue. After putting it in to her local garage they informed us she had contaminated fuel and that there was water in the diesel tank... they failed to keep a sample so I can't confirm this but they ended up having to replace the fuel pump & filter and sent the injectors off for testing of which all 4 came back as buggered so we're replaced.

After all this they said they still had issues and was finding filings in the fuel so apparently completely emptied and cleaned out the fuel tank, had to replace another pump and filter and so on and after giving it back to us along with a close to £4k bill it's still got issues, it generally drives fine but when you put your foot down or go up a steep hill the glow plug light starts to flash and I believe it does into limp mode... it will then run badly up until the point where you switch the engine off and on again and then will instantly run smooth again up until having to put your foot down again.

I'm very suspicious that water in the fuel was ever the issue, not to say they didn't find some water in the fuel, but a few days prior we'd run the tank close to empty and it was running perfectly fine, we filled it completely up and had done around 1/2 a tank of diesel with it running perfectly and then it just suddenly went (supposedly with a clonk which doesn't sound like a contaminated fuel issue to me).

The garage is currently at the stage of not knowing what to do any more, we are at the stage of wanting to sell it but at the same time it's only got 80,000 miles on the clock, in my opinion the engine should be good for at least another 100,000 miles.

One thing I recently read which I'm wondering if that's causing the issue is that injectors potentially have to be coded to the vehicle, if that's correct and the garage hasn't done this could this be what is causing the engine to go into limp mode and then be perfectly fine after a restart?

[Doc]

Welcome to the forum.
Sounds like you've had a right headache with your caddy.
First up, get yourself a proper live diagnostic test to work out for certain why the limp mode, my guess would be a boost or fuel pressure issue.
It's unlikely to be an issue with injector coding if all is ok up to the point where you put your foot down fully.

[Joe swoonara]

Seem like the garage is trying to diagnose a problem by using your money to do so , as Doc says get it plugged in and see if it's sending any codes would be your 1st port of call , good luck with finding your problem