Hi all, a tech question for you. Firstly a laugh, as I was trying to jump start a van, and stupidly connected the cables the wrong way round. There were sparks and I immediately removed them. Luckily later in the day, my car actually started-I had visions of a 4 figure sum involving the electronics etc.

Trouble is although it starts, the engine idles quite roughly and the light is on, on the dashboard. Any ideas as to what could be the problem? I haven't driven the car as yet. The battery was brand new, and I plan to check fuses and stuff, before I call out a mech.