weve got an 03 Seat Toledo which has a constant stream of air bubbles running along the transparent fuel line. once the car is started it doesnt seem to affect performance, but heres the wierd thing: start after 8hr day at work OK. start in the morning, hmm, needs at least 2-3 goes, it just catches then stops, before it finally starts. ive bought a new fuel filter, £24 HOW MUCH!!!, and the plastic T piece £20 HOW MUCH!!!. so before i fit the T piece id like to know if it is probably going to be an air leak here, or if i should be looking elesewhere. the VW stealer said it could be the electric lift pump, cant see this myself as how does that equait to getting air in the fuel system. one other note, the garage that used to service it said the reason they fitted a new fuel filter and two cans of fuel cleaner was becuase: the previous owner tried some bio-diesel, hmm.