My car idles fine at about 750RPM until i turn the lights on and the RPM goes up and down. Any body now about it or know how to cure it.
Thanks

 

Does the idle speed hunt when the AC is on, the clutch pedal is depressed and the shifter is in any gear? If so, check the clutch pedal dis-engage switch. It is located on the bracket where the clutch pedal lever rests when the clutch is disengaged. The switch is a very cheap part (@$15 US at the dealer) but can be fixed. It likely has a broken coil spring inside that is preventing the switch from closing (and sending a ground signal to the ECU) when the pedal is depressed. Check by pulling out on the plastic rod.

 

Oh, and the lights have to be on too!