Hi all I own a mark 1 Sharan Tdi on a R plate which is running rough, my mechanic said the pump is not pulling enough fuel, he filled up the diesel filter and it ran fine, but gradually became rough as the fuel drained from the filter. i just want to ask if these cars have a low pressure pump and a high pressure pump. And if anyone else has had a similar problem. And could this problem be caused by clogged fuel lines. many thanks