Hi all,

 

Hoping there's some experience out there that can advise, I bought my mum a 2005 Fabia mk1 1.2 with 87k on the clock, full service history etc. I thought was a good car.

 

Anyway it has now developed an intermittent misfire (it seems) as the engine will loose power (like running on 2 cyl) but this can be rectified with the application of a lot of throttle. It's an odd one as some days it does this a few times, others none at all and runs fine.

 

Being a 3cyl if you loose one the impact is bigger (3rd of power plus pumping loses) but it's never actually stopped or broken down.

 

I've checked fault codes with a cheap OBD2 scanner and nothing, it's been to a garage an on a Snap-on solus pro (or whatever they use these days) which also found nothing logged.

 

I'm thinking it could be a coil, but wouldn't this throw up a fault code? I think we are going to put in 3 new Bosch coils as its £75 to illuminate that and they may be originals at 13 years old.

 

I'm not too familiar with VAG petrols, I've always had diesels due to my drive cycle and mileage so I'm not clued up on petrol engines. Could it be the throttle body or throttle pedal/sensor? I'm thinking this car is DBW.

 

We have had the common issue of leaking rear doors (terrible design, I work in the industry and understand why VAG did it but it's just a pain to work on and when the seal fails) this it seems has effected the electric windows (no longer working) and now in the process of trying to dry out the interior. Could water ingress to the interior be affecting the engine running? CANBUS surely works in weird ways and I know it's not unheard of for completely unrelated parts that are faulty to effect other unrelated parts due to false CANBUS signals.

 

Anyway any help/advice appreciated

Have a good look at the brake servo vac hose, especially where the hard plastic hose sections connect to things.