Misfire under load and air lock in fuel system caused car to breakdown and stop!

[dmhelsby]

My vehicle: 2007 Passat 2.0 Sport DSG Estate
Thought I'd just add my two pennyworth in case it helps anyone out there?
I've had a strange intermittent purring noise coming from the rear and have also heard it temporarily upon switching on the ignition. This has been coupled with a loss of power and 'misfire,' (I thought), when shifting into S and flooring it to overtake someone!!
It's had at least 3 computers plugged in and no fault codes were found. It's finally been sorted after nearly a year of putting up with it, by Lion Garages, Leicester 0116 262 2044. Not only was the fuel filter black, after having had it changed 20,000 miles ago which is the service interval, the fuel pump lifter was broken so a complete new pump was fitted. This, along with a new auxiliary belt, as the old one got covered in diesel when the brilliant AA guy got me started again by opening up the fuel filter housing and getting the diesel to flow by knocking the underside of the car with a hammer.
Car is now running like new .... not bad considering how much I've spent on it recently.

[RichardSEL]

There's no monitoring of primary diesel pump flow in CANbus. So flow fault there wont show on diagnostic. The gunk forms up the side of the pump filter that's can in shape. Knocking the pump can cause some gunk to fall from the filter side so fuel flows. Filter cannot be changed separately. The filter in engine bay you had changed 20k miles ago isn't that one.
Some filling stations' tank cleaning regime is poor. Some pumped Derv is dirty.

As an aside. Currently fighting a Citroen DS23 (the Bertoni-styled one that the fashionistas swoon over) with a dirty petrol tank. Tank filter's been removed before me, and an external inline plastic cartridge one added. Except it silts up every 60 - 80 miles causing conk out. At the most convenient places: red lights, partway onto roundabouts, junctions, etc. Cost of new tank £680 +VAT + 2 hours take out + 2 hours fit + cartage + VAT. Or removal, cut open, clean, seal with special paints, re-weld, refit: £280 +VAT + all the rest. You got away lightly, as I've already had all the lines and carb stripped and cleaned (£200 +VAT)