passat b4 1z starting and running problems x2

[davec495]

hello there i have two passats and they both seem to be having the same problems with fueling firstly the one with 64 thousand miles on the clock starts but alot of air comes down the clear fuel line towards the pump from the filter and runs for a few seconds then slowly the revs die but the fuel consumption got realy bad befor it died lucky to get more then 15-20 mpg driving like a granny only modification is a two inch straight through with dtm backbox

second car 140000 thousand miles
seems to be kicking alot of black smoke out and noticed when i looked today that air was in the fuel line on that one aswell causing it to run lumpy one of the fuel lines had been rubbing an air pipe so changed that but still air coming down has just had a new fuel filter on aswell any help would be welcome


thanks in advance    dave

[hodgy_7]

You forgot to mention that if you rev both over 4000 rpm  when they drop back to idle they sound like a lister engined dumper.

[davec495]

haha how could i forget