Fiat Punto Lambda Sensor Problems

1. very uneconomical on fuel 2. lack of power going uphill 3. sluggish to catch speed ( as if advance mechanism not working; i seem to understand that its all electronically managed) I WOULD LIKE TO REPLACE THE LAMBDA SENSOR ( QUITE TO...

After a couple of minutes from cold car gets to 2 and a half thousand revs and cuts of till you ease off again. If you hold the throttle down in neutral it revs up and down on its own at about one second intervals at the top of each rev th...