Elecrical fault

I have a vauxall astra 1.6 club easytronic and it seems I got a problem with the electronics, the problem is that sometime when you try to put in reverse it will flash for time and not recognised it, then it does the same when you start of it will only go into a2 or a4 not all the time, then sometime you press the brake pedal in to start the car all light come on but engine want start I try it a couple times the it will start then another thing it does it will change down on a hill and will cut out a few second and it will go ok then