My ford ka engine stops when i put the brake at the trafic light and somethimes in driving . i have change the throttle position sensor and it still does the same . the car engine then starts straight away and goes until i put the brake again . Any ideeas as i want to fix the car - maybe the petrol fuel filter can be the problem ??? Please let me know otherwise there is no point to go to a graage where they gonna charge 60 pounds an hour just to investigate the problem .