Now, before we all panic... I'm not looking to create mass hyseria here but I have discovered a slight issue with the plugs fitted to my car and it may be a one off, but it's something that I've never experienced before in all my turbo driving days.
Basically, fitted a set of GM 'VXR' original spark plugs about a month ago (or about 500 miles) which came in the box branded as NGK PFR6T-G and all was well. To cut a long story short, the car is running FMIC, full exhaust and a pahse one map however since they were fitted I can hand on heart say the care has never seen over 4000rpm... put it this way, I'm averaging 32mpg!
Tonight, ahead of a remap on Friday I took them out just to double check the gaps and to ensure they were tight etc... in effect, just faffing about.
This is what I found:
Ever plug has hairline fractures in two of more areas of the ceramic insulator and number 4 (nearest the battery) has actually fractured a large section off which I did recover before it fell inside the engine thankfully.
What caused this is beyond me, the car runs at perfect temps and I haven't been thrashing it senseless for the past few miles either. It's had a steady run to Devon and back and the rest has been the daily commute into work.
Incidentally the car was MOT'd today and failed miserably on emissions, which I put down to the 200cell cat or a mapping/fueling issue. Whether a possible fuellng issue could cause this, if the car is running lean and thus hotter... is beyond my technical abilities but there is obviously some reason this has happened.
Any suggestions greatly appreciated... although my pressing issue is the car is now strandaed and I'm understandably reluctant to use these plugs even to get to the nearest spark plug shop!