Revs hunting at idle / whistling noise?

[barlimow]

2007 mk5 GTI (85k miles): revs have started to "hunt" at idle. Will go from about 800rpm to 1500rpm, and all inbetween. I also hear a slight whistling noise as well.

The hunting I think is the PCV valve (but that's just from my very limited knowledge of such things!), but not really sure about the whistling - could it be a slight slit in a pipe, or related to the PCV?

The car is already booked in for a service on the 16th March - is anything likely to "fail" before then and leave me stranded, or as long as I take it easy can I probably limp through another week?

Any advice appreciated. Thanks.

[AndyBrown]

Check the DV for the whistling, that might split.

[Saintsteve]

Sounds like the PCV valve has actually blown as it has a small hole in the casing, in which if the diaphragm inside goes, your hear it hiss especially as you shut the engine down on the key .

[PhilNUK]

I had the hunting at idle issue about 6 months ago....

I replaced both the PCV and the DV and it fixed it... Worth doing both I think just for reassurance and they aren't expensive parts..

[GTiBlues]

I've still got my hunting at idle. Only hunts when you go into neutral at traffic lights or when ever you come to a stop. I've replaced PCV and DV in the last month.

When I opened my door after unlocking. I heard the fuel prime but this time it was hunting to prime. Never done that before, it's always been the usual hum for a second or so. My guess now is my fuel pump at the fuel tank end that's giving up. That's next on my list.

[Saintsteve]

I've still got my hunting at idle. Only hunts when you go into neutral at traffic lights or when ever you come to a stop. I've replaced PCV and DV in the last month.

When I opened my door after unlocking. I heard the fuel prime but this time it was hunting to prime. Never done that before, it's always been the usual hum for a second or so. My guess now is my fuel pump at the fuel tank end that's giving up. That's next on my list.

Have you checked your fuel pump cam follower? Sounds like that's Knackered if your saying that.

[GTiBlues]

That was just replaced 2 weeks ago. Still no difference.

[Saintsteve]

Find someone with VCDS and get them to check your fuel pressure, may be a low pressure pump issue in the fuel tank..

[GTiBlues]

I've got vcds. I know it's my pump at the rear, just need to know which Walbro one to get. I did make a topic but no one said anything yet