GTI-6 idle control valve

[L95]

Hi

My GTI-6 is idling much higher than usual. Gets close to 3000rpm when I start it up in the morning and once warmed up the revs tends to keep hunting between 1250rpm and 1750rpm.

A bit of research suggests this is almost certainly the idle control valve.

But one other thing it has started doing is trying to pull away on its own below 2000rpm. For example, on a flat road in sixth, it will go along at 40mph on its own without me even accelerating. I'm guessing this is also a symptom of the idle control valve?

Any help much appreciated!

[DeeTurbo]

That sounds like an air leak to me.

I've heard that the resonator under the inlet manifold can crack.

Some people try spraying brake cleaner around the area they think an air leak is and listen out for the revs to rise.

[Mighty306]

As above, air leak is worth investigating first. Brake cleaner or carb cleaner are a good way of finding the rough location of a leak. The engine can burn either as a fuel which is why the rpm's rise when its drawn in through a leak.

BUT .....be really careful. Don't spray it around the bay when the engine is hot as it can be ignited by a hot exhaust!!

To check the ICV you can use a multimeter to check resistance across the pins. You should see approx 55 Ohms across either the two outer pins or the two inner pins.  Also you can detach it from the throttle body but leave it plugged in. Get someone to turn the ignition key to its second position (without starting engine). You should see the ICV move. If no movement at all its stuck. If it does move it doesn't definitively tell you its not playing up tho.