General Not keeping the idle 900rpms.

[bowiemlt]

I had my punto 55 for almost 5 years now. it always gave me a problem with regards to the idling. Sometimes it works really low worst case jut switched off. Then the cure is i switch it off for 5 mins resrtart the engine and works flawlessly :S I can't understand. I checked the ECU coils, plugs & high tension leads, changed the temperature sensor aswell . But still does not stop doing it every noe and then.

Can it be the ECU? or is there any other sensor I might take a look at?

Thanks for all your replies..