hi, my wifes car has started losing power. its an 02 1.9tdi ambiente.

it starts fine and will run great initially, after a min or two of giving it a bit of stick its like it goes onto 3 cylinders, no power as such, you have to gingerly press the pedal to get an increase in speed, if you sink the pedal it just bogs right down.

if you pull over, switch off then switch back on again everything is fine, you can boot it in 2nd or 3rd but when it hits 3000rpm its like what ive read "limp mode"

ive pulled the maf sensor and its just the same, one thing i noticed is quite a bit of air in the clear pipe going from fuel filter to engine, when revving the amount of air running through the pipe increases with revs. with engine stopped there is always a bubble in middle of pipe about 20mm. it must be drawing air from somewhere as i take it this isnt normal? would this cause the problems described?

sorry for a bit long winded :oops:

any ideas lads? will the air be causing it to go into limp mode? where should i be checking to see where the air is being drawn in?

any advice appreciated.

cheers mick

Does the fuel filter have a bleed tap underneath it?

It sounds like you've got a porous fuel line that's drawing in air when the engine's running. Finding this requires a methodical covering of all the joints in the system, and then the pipes.

Reasoning being that you shouldn't have a persistent air bubble, and that the bubble will stop some of the fuel flow, and a diesel only stops accelerating when it runs out of available fuel in cylinders.

will get a look at her filter when she gets back on sunday. would excessive air in the line trigger limp mode?

thanks for the replies guys.