As a few of you will know, i run Denso Irridium IK31 plugs in my car

anyway, on the way to the blackpool pissup last week, i noticed a small misfire when accelerating in 4th and 5th and a bit of unburnt fuel out the back.

upon inspection today of the sparkplugs, 2 of them (numbers 3 and 4) had showed signs of a heat related failure.

#3 plug = the insulator was slightly loose in the body of the plug

#4 plug = the whole insulation was freely spinning round inside the plug and carbon had blown up the middle of the plug



This also happened when running IK27's in germany aswell on one plug, but on a different cylynder (number 1)





has anyone else had any problems with running these plugs - IK27 or IK31 in their cossies? as at 40 to 50 quid a set, they are bloody expensive to only last 4000 miles