Hi, i need some help with my car. I have a 06 plate Ford focus, last week the engine management light came on on the dash board and when I put my foot on the accellerator it lost power and jerked alot. When I drove the car again it still had the same symtoms. Then there was a plume of black smoke and it went back to near normal! Someone thought it was the ERG valve and recommended I get the valve cleaned. I have booked it in but is this the best way of sorting it. Is it the ERG valve. I also wanted to know if it was easy and will it cost alot.