95 Windstar

This can be the case, I would first get a head check done, this is a simple chemical test to detect Co in the cooling system, if so you will have a head problem, do the test first.

Mark (mhpautos)

Another test that you should perform would be a cylinder leakdown test. Another possible cause of your problem would be a leaking intake manifold gasket and the cylinder leakdown test would distinguish between the 2. The history would meann a lot in this diagnosis. If there has been a severe overheating recently, that would tend to point to a head problem. If this issue developed without a previous overheating, I would lean toward the intake gasket.