Revving on idle

[chipmunk82]

When warmed up, idling or just dipping the clutch on my ED30 makes the revs go up to 1500/2k and back again sometimes repeatedly! Bit unnerving!
I have undone the oil cap and pulled out the dipstick and both make the engine run rough as if its ready to cut out so does that mean I can exclude the PCV? It has a GFB diverter valve so I'm hoping that's not the issue either. So possibly a boost leak somewhere?
I recently had a superchips type map put on which seemed to be spiking so took it back and got a tamer version, due for a custom map next month so it needs to be running right!
Haven't checked vagcom yet as don't have it currently!

[Tal001]

My car did the same thing, it's got no mods.  I took it for a service and when they scanned the car with vdcs it had three faults which have been cleared and it hasn't done it again.  I'd get a scan done ASAP

[chipmunk82]

I've got it booked in on Monday to be scanned but in the meantime a heads up on what pipes could be split would be good if nothing else but to save a bit of time at the garage. It seems likely to me that a remap would make the tiniest of splits more apparent? It's just finding it!
I have a k&n panel filter, gfb dv, pre cat delete and stage 1 map.
Thanks in advance!

[lukemk5gti]

Last VW had high idling revs due to a split pipe onto the throttle body.

It needs a vacuum to run so any air ingress will up revs.

I couldn't even see the split and my mechanic told me it was a dirty throttle body.

Have a feel around and get a good torch.

[chipmunk82]

It doesn't sit at a high idle it goes from where it should be up to 1500/2krpm and back again repeatedly. Does this make a difference?

[Scottymon]

Mine did it for a while, it wasn't long after the Throttle Body died; massive drop in power and EPC light. 

Worth checking the pipework, esp. to the TB and make sure the jubilee clip is tight. 

If it turns out to be the TB, changing it isn't too bad of a job just a bit fiddly with its location, not heard of the latest Revision Q version dying, so a second hand one can be fitted saving LOTS of cash over the new price. 

But get it scanned and copy the codes before clearing and paste them up here.

[Saintsteve]

blown or damaged PCV valve is your problem ,

[chipmunk82]

My first thought was the PCV valve but the engine runs rough with either the dipstick or the oil cap undone so I thought that would rule it out?
Taking it to a garage Monday to be scanned and will mention the TB but I'll try and find out what the codes are, eml light came on yesterday and fuel economy has gone out the window :(
Meant to be driving 150 miles later hope it's not going to damage it

[Saintsteve]

Just so you know a blown or damaged PCV will not show as a fault via VCDS.

For the sake of £35 , this will save you over buying a throttle body if you haven't changed it before.
Mine done EXactly the same fault as you are describing as have 100's of others that post this fault before.

[Scottymon]

Where are you based bud, shame you can't find someone local to scan for a couple of beer tokens.

It might well be the PCV but don't throw money at things before you know, a second hand TB Q revision can cost around the same ---

There's a VCDS register on here somewhere...

[chipmunk82]

I will probably get a new pcv for it now regardless, it sounds like something that will go sooner or later anyway but the Tb will be a handy place to look if no luck or leaks found!
I'm in Gloucester area usually but down in Devon at the moment and booked in anyway on Monday for new brakes fitting all round. Eurocarparts have an online sale and I got discs and pads all round for £185. Next time round will upgrade the front pads to DS2500's. 

[howie1987]

I don't know much about vw as i'm quite new to them but on my old car before the golf i had this exact problem and it was my throttle body sticking. It only did it when idle,once driving it was fine.

[sanj]

My Golf R did exactly the same thing and it was the PCV.