at 55,000 miles the gaps on my factory plugs (MY02) had opened up to well over .051" due to erosion of the electrodes. By 100k miles they would have been in pretty bad shape by my estimates. So I'm glad I checked mine when I did. It seems like every s2k is a bit different, some have had plugs last a long time and others have had them fail sooner. That's why I like to check them once and a while.

 

Thank you all very much for comments.
I should check my plugs often.

 

Back to the OP, I would get your injectors cleaned as you may find the injectors on the two burnt cylinders are running slightly lean.

I would also check the exhaust headers for any leaks on the manifold gasket, or cracks in the pipes as air leaks at the head flange can also burn up plugs like that.

 

Thanks for your comment. I'll check them as you suggested Chris.

 

He is right about the lean (lack of fuel being injected into the spark) would def cause some fire issues.


Are those ceramic plugs? because if the plugs are not torque properly, vibrations can cause serious damage on the plugs.


Should also check the wires for a complete seal, if there are exposed wires, arcing can occur and it may be affecting the firing sequence of the plugs.

Additionally, it's probably safe to reset the ECU.

Try using higher octane fuel

Consider a safety precaution: Why do some spark plugs have multiple ground electrodes?
This is an attempt by the manufacturers to increase the service life of the spark plug. The ground electrodes can wear down rapidly in some engines. Tiny particles of metal are removed from the ground electrode each time the plug fires hence they gradually wear away. There is a misconception that a multi ground plug will produce mutiple sparks - this is not true, only the nearest electrode to the centre (i.e. currenty the longest) will spark, as that becomes worn, another electrode will become the longest and replace it as the sparking electrode.

Regards,
Kevin
wongs.kevin@hotmail.com