Rough idle.

[snake16valve]

Hi all.
My latest problem with my car is that when it is ticking over the revs are going up and down like mad.
It will idle at 1100rpm fine then it will drop to as low as 300rpm then up then back down all the time.
Some times the damn thing even cuts out when i come to a junction.
I have checked all the hoses and my inlet manifold to see if it might be drawing in some air.But they all look ok.Also cleaned my idle control valve.
Please help what else can i try ?
My car is a 1991 mk2 golf gti 1.8 16v kr engine code.

Thank's for any help i get ! Also thank's for the use of the forum !

[Ktuludays]

Check isv. if it buzzes then it is working ok. give it a good clean with carb cleaner or soak in petrol.

also check electrical connections on throttle over run switch. top of throttle body

[Judderi]

Double check all your hoses. I had this and it was the little pipe under the ISV had come off. Also check the throttle position switch. Make sure its clicking when the throttle is closed.

[Brads MK2 GTI]

Check the idle switch.

[snake16valve]

Thank's guys for the help.
I think that my throttle switch is goosed ! It's not even touching anything and also the little micro switch is not clicking...Does this sound like the thing that you are speaking about ?

Thank's again..

[Gambit]

aye that really needs to be working

you can test it my holding the throttle above 2k rpm & pressing in the micro switch. the revs will drop if its working

[snake16valve]

Hi again gambit, thank's for that info.
I tried the switch i pressed in the little red button and nothing happened no clicking sound ! I think that the small spring inside the switch has gone.
Where could i get a new one of these from ?
Can anyone help me with a part number for such a thing ?

Cheer's again....

[Judderi]

I will warn you now, there not cheap! I needed one a few weeks back and there something like 50 or 60 smackers new. I managed to get one from a scrappy for £20.

Part no.

027 133 061 A

[Veedubgt18v]

mate they have well gone up in price then! i got one a couple years back and they were like 25 quid!!  scrappy job the tbh or a micro switch from maplin or something if your handy and electrics lol

[snake16valve]

Thank's for the info and the part number.
I think i will be going to the scrapys in the morning....

Cheer's guys !