Quote Originally Posted by ryan12473 View Post
In his case it probley is the timing mines not modded but on mine im sure its intake gasket leaking which would make it lean the plugs had 100,000 miles on them, and only one was damaged. It also has a code from the rear o2 of bad catalist does this mean the cats burnt from raw fuel or is it the sensor it self.Also do know if a 99 gtp has exhaust manifold gaskets in between heads and manifolds,if not how do i fix them from leaking. Found this out when I seafoamd it.
Intake gasket might foul out a plug. Its not going to Lean a plug. Or melt a plug. Your rear cats probobly clogged, and yes theres a gasket for the exhaust manifolds
And who runs plugs for 100K miles