From post #15I have the exact same problem with my 2003 Marquis. The the sparkplug/coil well was full of coolant and my blue driver sent me right to it. My question is weather there is coolant circulating in that plastic intake manifold.
"Coolant does not pass through the entire manifold. Only through the aluminum part (on an original manifold) in the front and maybe the rear. "
Which spark plug hole has coolant?
Is the manifold a replacement or an original?