hi all just wondering if anyone could give me some pointers. my 3door started missfiring today between 3000rpm and 5000rpm. took the plugs out and found the plug from cylinder number two to hav lost its electrode tip.looks to have burnt off. anyone have any ideas why this could have happened and wot i do next???many thanks

 

that could of happened due to lots of different reasons ie old plugs,wrong plugs,running too lean and I'm sure a few more reason are out there!

 

Most likely is wrong heat range as said, what plugs are they and what stage of tune/bhp, they do NOT do it due to age.
tabetha