OK read a few threads on this subject, but am still at a bit of a loss. My Pug idles occasionally at 2K RPM's. I put in a known good idle air valve and gave it a cleaning just to be sure. If you disconnect the valve while it is high idling the idle goes back to normal. Reconnecting the valve it will still idle normal for a bit, but then will shoot up to 2K after a bit. The only thing I can figure is that its getting a wrong signal from the ECU, or the harness is damaged. Any help would be greatly appreciated. Thank you,

Jon

Try cleaning out the throttle body with some carb cleaner. Could be a gummed up butterfly

Mine idles at about 900 to 1000 and sometimes when I am driving and put my foot on the cutch without engine breaking it goes up to 1600. I have cleaned the idler valve and the Throttle body (closes completely). Had a guy come into work once who said that his friends 405 was over fuelling badly so it would shoot up to prevent from stalling. I notice that my exhaust does smell like petrol (no black smoke though) is it possible that a worn air flow/temperature sensor or possibly worn injectors could be causing over fuelling and maybe the idler valve is opening up to compensate? could explain why the revs shoot up when you plug it back in? I am a complete novice at this so I might be completely wrong, but to me it seems to make sense.

hi idling can be a result of a faulty or baly connected heat sensorto the right and below the thermistat housing blue in colour if its not connecting the ecu thinks the motor is cold and ups the idle and ritchens the mixture also i keep my throtle cable loosly adjusted as haveing it tight seems to produce these symptoms when hot regards pugs

Took mine to a Pug guy, He reckons that the last garage tried to tune it and screwed it up, giving me an air leak. So now i'm over fuelling like a bitch and missing 40hp. Any one in NZ DON'T GO TO SAXTON AUTO IN PETONE!!! They also screwed my rad fan up somehow so now its ALWAYS on.

A high idle (2K) is a result of a faulty, or incorrectly adjusted, throttle position sensor. The idle position switch goes open circuit. They just wear out over time.