On the way home from work today. My GSI lost a cylinder, the emissions light came on and the traction control light!! I cleaned the spark plugs as one was black. It now runs fine. Not long since had a service and the sparkplugs should have been replaced. Any ideas why it would be causing this?? Also if i take it to vauxhall should i take the dumpvalve and induction kit off??? Will this void my warranty??? Has anyone taken their car in with mods on???? Oh and the emissions light still hasnt gone off!! Will vauxhall have to reset this?