car cuts out when you let the revs down

[aaron1980]

Hi thanks i will have another look at it over the weekend. the mot man has gone on his holidays so it wont be heading down to newquey this year anyway

[kmpowell]

plastic valve behind the airbox trust me clean it with brake claner or petrol or any thing to flush the sh!t out. i've been there, i've got a 16v gti and had this problem for ages, tryed replacing the isv and adjusting the timing and co, no good (to me). i've seen so many people on here goning on about this problem and i keep saying the same thing, but belive me try this before replacing things it's gotta be the cheapest option. let me know how you get on i'll hang my head in shame if it dont sort it out.

Mine has started occasionally doing this when dropping rapidly from high revs (e.g when dipping the clutch for longer than a second) - but with me being a complete engine simpleton, can you describe/show EXACTLY where this 'valve' is? I had a look last night, but nothing was obvious to me.  :embarassed:

[rubjonny]

look on the back of the airbox, theres a big black/grey plastic valve. has 2 big pipes to airbox/inlet boot, a 2 pin electrical plug and a thin vac hose. Only on 16v models tho so if its an 8v you wont find it

[Gloves88]

Sorry to steal the post a bit, I have this same problem but on an 8v....do i check the same things or is it different?

[rubjonny]

everything conker says is valid on an 8v, except for the over-run cutoff bit
in addition if it a digifant check the idle switch clicks when throttle shut, throttle cable isnt too tight and the wiring to the throttle switches hasnt snapped. oh and check the setup as per the digi faq

[Gloves88]

everything conker says is valid on an 8v, except for the over-run cutoff bit
in addition if it a digifant check the idle switch clicks when throttle shut, throttle cable isnt too tight and the wiring to the throttle switches hasnt snapped. oh and check the setup as per the digi faq

Great, cheers

[bong69]

plastic valve behind the airbox trust me clean it with brake claner or petrol or any thing to flush the sh!t out. i've been there, i've got a 16v gti and had this problem for ages, tryed replacing the isv and adjusting the timing and co, no good (to me). i've seen so many people on here goning on about this problem and i keep saying the same thing, but belive me try this before replacing things it's gotta be the cheapest option. let me know how you get on i'll hang my head in shame if it dont sort it out.

Wow! just done this and 'ping' problem solved!!!

Cheers all, what a wonderful resource this place is!

[kmpowell]

Anybody know what this valve part is called? I have found out that mine has a split in it, hence the problem I was having. So it needs to be replaced.

Is it still available from VW, or is it a breakers job only?

[kmpowell]

I've now made a few calls to various dealers/breakers/parts suppliers. Bottom line is that these are only available from VW and the part number stamped on it comes up as a 'Deceleration cut-off valve' on the dealers parts system. This would make sense because not only does the name explain the root cause of the problem, but it also ties in with what the poster who told people to clean it, stated.

The part number is "027 133 985 A" and costs £66.61 from the dealer. Unfortunately it's back order only, so it could be some time before I get my new one, 10 days at least according to the dealer.

[kmpowell]

The part number is "027 133 985 A" and costs £66.61 from the dealer. Unfortunately it's back order only, so it could be some time before I get my new one, 10 days at least according to the dealer.

Just had a call from the dealer, the valve has arrived already! 6 days for a back order part, not bad!