Spark plug quenching.
 

Read it, click on the pretty pictures, and understand it, fucksluts:

http://www.ngk.com/glossary.asp?kw=Quenching

Now, plugs die quick if the tune is a little off, wrong plugs is being used, or you are pushing limits. This is a trick to add to the bag, once you master basics like non running basemaps and running the correct sparkplugs.