have similar prob w/ our revo 99 model, spark plug brand is AC DELCO 43XLS installed by RAPIDE Pavilion Binan Branch last feb 2005,i forgot to replace it on the next change oil last nov 2006 on its 9K km. seldom used ung oto kya mejo tagal ang interval ng change oil and fullysynthetic gamit ko.it happend last may 4,2007, bro ko me dala ng oto, few meters from the parking lot, bigla me lumagatok sa engine room when he checked it one of the rubber cover protecting the spark plug was removed and nakita nya wala na ung half ng spark plug(from the metal part upto the ceramic part) in short wala na pwede kapitan ung wrench pra matanggal sya. so top overhaul ang ginawa pera sa ibang rapide branch ko na dinala. the said spark plug has been used for 12K km before sya maputol, may tendency ba talaga maputol pag ganyan katagal nagamit? appreciate ur advise, coz we plan to file a complaint re the said damage.by the way people frm the other rapide branch said that the said model of AC delco Spark Plug has been phased out since 2006 as there has been several negative feedback on the said plug.