Hi all,
I was very pleased to get an Audi as I have always wanted one and got this car recently as we dont have a lot of money. But then issues started to arise. Recent work done had been vacuum valve and crank sensor replaced.

First, discovered a flooded plenum chamber and water in relays under ECU which caused limp mode plus soaked carpets inside drivers and rear passenger behind driver side. Cleared blockage and dried out relays and all appeared good.

2 days later I got CEL light and code P0230 but car still ran fine.

3 days after this, as I was arriving home from a long drive on motorway the car started to stutter at about 10mph and then when I parked up and started it again, rpm was jumping up and down in idle and stalling, then it cranked but wouldn't start. I then replaced relay 219 under ECU as it appeared to have corrosion on the contacts. Cleaned electric contacts on relay holder. All other relays and fuses appear to be fine. Car took a little while to crank but once it did all appeared good again.

Drove for another 2 days with no issue, then today while driving, engine started to shudder and then stalled at 25mph losing power steering. Took about 3 minutes of cranking with foot on gas pedal to get engine started again. This happened 3 more times on way home but did make it back. No codes have come up at this point.

I have been advised to replace diesel fuel filter as first port of call but I'm worried I'm just going to be throwing money at it. Does anyone have any idea of the likely reasons behind this happening? I'm a novice mechanic i.e. brake pad and filter changes etc, I just hope someone has had the same symptoms and has been able to fix.

Thanks in advance all.