Evening all, So I've got an A4 TDI 170 and recently its been kicking out pretty substantial amounts of smoke with unburnt diesel mixed in for good measure. There doesn't seem to be any real pattern for when it happens but when it does, it can get really crazy and leave serious smoke clouds at the back of the car! I've just spent ages reading various threads on here using the search bar, in the usual fashion, but I'm still unclear as to what to check first and what it could be. VAGCOM hasn't thrown up any fault codes and apart from the smoke, the only other thing I've spotted when looking over the car is oil in the diesel filter. That said, there's not huge amounts and I'm not losing so much that I'm having to top the oil up. No issues with low coolant levels or anything else like that either.......so I'm stumped! From reading through the search results the tandem pump seems to be getting mentioned quite a bit but as it's not the cheapest of parts to replace on the off chance it works, I thought I'd test the water to see what else you guys thought it could be? Or if there are any tests I can do to try and figure out what the hells going on? As usual, thanks in advance for any help you can give!