Right, here's the problem, 16v 1999 Astra with a misfire. This occurs under acceleration, the car seems to cruise alright. When idling the misfire is not regular, sometimes a little burp or two every five seconds, then maybe every 12 seconds and sometimes ok for a little longer. The car is a bit of an oiler, a tad over 1/2 litre every 1k but it's been like that since I've had it (November). I've had a new backbox to replace the knackered original with the collapsed internals and I've put new plugs in. Checked the plugs after 100 miles and they were dry and clean as a whistle, the old ones had no worrying colours though they were worn.

Would I be right in thinking the fact the plugs were not oiled up would point to an electrical fault rather than rings or valves?