Re: Mk3 16v GTi Idle Problem - With Video!

[ozza]

This just started today.

The car just won't idle at any temp of engine.

It does 2 things.

1). Start engine and it starts every time but pulses the idle RPM to just above stalling, then raises it to around 1300 RPM and then drops it again to around 700 RPM and continues like this.

But it will drive fine, except for when you take you foot off the throttle when it seems to jolt a little.

See this video (5 mb) to see whats happening. I am not touching the throttle at all, just twisted the key to start it.

http://www.buryhillbikers.co.uk/Video/car1.mpg

2). Once you get the revs up after sympton 1). by pressing the throttle, it will rev fine but when you let off the throttle it starts idleing at around 1200 RPM and slowely rises to  2000 ish RPM and then drops to 1800 and then rises to 2000 and cycles like this from then on.

See this video for what I mean, again I am not touching the throttle:

http://www.buryhillbikers.co.uk/Video/car2.mpg

I replaced the ECU relay 3 months ago due to a misfire issue so that is now brand new, idea's what could be causing this???

All help greatfully received.

Ozza

[rubjonny]

I'd go with an air leak, check all your vacuum hoses and the intake boot for splits.  Also check the joins at the inlet manifold for leaks.

[Overseer]

yup vacuum leak.. 

[Len]

Wow! Good to see the 'Seer back! Been away too long mate!