[Engine] Revs going up and down

[ryan.m]

Hi my 2001 berlingo has started to act strange the revs will go up and down  then will settle i checked fuel lines and found air in them inspected fir any leaks have found nothing leaking or damp

Has any one had this problem

[brodfather11]

The fuel pump sucks so it will suck air into the fuel lines , does not always let fuel leak out .

The primer pump and the fuel filter seal are the main culprits

[ryan.m]

Cheers for the reply

[dumdum]

Presuming it's a 1.9d with clear fuel lines? If the crank sensor goes down this will often result in funny revving and all manner of knocking when the pump timing is cocked up...

[ryan.m]

Found the problem the feed line from fuel tank has two green o rings up at the engine were it conects to a plastic joiner both o rings replaced enigine now running fine and no air in furl system