if you don't know how old the plugs are change them...also do the plug wires and all the ground wires (you can make your own out of 8 gauge monster cable with some good terminals and some shrink wrap to put on the ends to prevent corrosion)

spark plug chamber?...not sure what exactly that is but you probably have a leaking spark plug seal on your valve cover...it is an easy fix with some new rubber gasket or you can put on silicon gasket maker on the old seal to help close it shut