has anyone experienced bosch super 4 spark plugs causing misfire? before christmas I had a bosch super 4 blow out of cylinder 4 resulting in a helecoil and new set of super 4's. yesterday cylinder 4 had obliterated another plug this time there were no prongs left on plug and no compression at all from cylinder 4 the garage have had my car for a day and half looking at it to try and find problem but cant without striping engine. thay are not charging me for looking at it. can anyone advise what I could do now if anything.



this six week old plug. whats left of it came out of cylinder four. the left plug is what its meant to look like