Has anyone came across this problem, on mine its the spark plug on the back side, all the way to the passenger side cylinder. I am on my 3rd spark plug and each one keeps caking with this white ash buildup. I am getting horrible gas mileage. I have 2 new o2 sensors which both have white ashy buildup on them and I have a new CAT that already has severely over heated to where there are discoloration burn marks in the metal. I had the intake gaskets redone in 02 or 03, and I was wondering if anyone seen this before.

More than likely it is antifreeze entering the combustion chamber, when I changed my intake manifold gasket I noticed all of my spark plugs had the white ashey buildup you described....sounds like your intake gasket is leaking again....the gasket has been revised since '02 - '03

...sounds like your intake gasket is leaking again...


I certainly don't envy you if it needs to be replaced again! I just did mine along with the head gaskets, do not recall ashey build up on the plugs, the only thing that jumped out were the long bolts for the lower IM being finger loose - but I agree with a_joyner in that something is getting in to your cylinders.