my Vauxhall Vectra 2001 LS keeps cutting out when hot so I changed spark plugs and coil rail and it worked fine for about 7 months then the same problem so I just changed my spark plugs and just one is very black on the bottom and there was a little oil on the thread any ideas

darren, June 2013

The blackened plug is not firing - hence the oil and soot. Change the plug for a new one. If problem persists fit new coil pack. If it's only 7 months old then it'll be covered by warranty. I'm surprised the engine management fault warning light has not come on!

popcorn, June 2013