Renault megane 1.4 16V high revs check injection?

Hi

I got a megane 1.4 16 V petrol

When start up i car revs are various between 0,8-1,9 even if idle. They just go up and down all the time.

Next thing is when you drive a car for about half an hour and engine gets warm and approaching rounabout or junction when you have to stop engine just cuts off and message is coming up "check injection"

Car wont start after that for couple of minutes. Even if keep trying. You think it does and then just cuts off imidieatly.

Run diagnostics and most intresting thing which came up was too high voltage on the Air conditioning sensor.

Tried 5 diffrent mechanics and nobody seems to know what the problem is.


Help ?!