I've got a problem with the spark plugs overheating. By overheating, I mean when the sparkplugs are removed they have a white glow where it sparks. Motorway travel, seems to be okay and after, the car runs fine on urban routes for a couple of days after. However when the car has urban runs for more than a couple of days or when the engine is pushed to its limit, then I get the sparkplug overheating problem, which results in the usual jerking etc. I can replace the sparkplugs, but the problem returns within 2 months depending on the quality of the sparkplugs. 1 week in the most extreme case.
Back in the eighties with distributor timing, and contact gaps, I would check theses things first but I haven't a clue with this engine with its computer control. I don't have a Haynes manual so I don't know where to begin.
Anyone with sensible suggestions? BTW the sparkplugs are the correct ones for the engine