juddering when turning left ?

I have a 1999 T reg corsa, it is running ok, except when I turn left it judders almost as if it wants to stall but doesnt, and a light comes up on the dash. I have referred to my manual and it says its an electrical engine fault. Then yesterday I went to pick my daughter up which involved taking a left turn but this time i turned left the light starting flashing and I had no power, the accelerator didnt do anything, it didnt stall tho. I am trying to get as much advice before I have to take it to the garage and get ripped off coz I have no idea about cars ANY SUGGESTIONS