On 3.9L V6 and 5.9L V8 engines, the intake manifold gasket may leak and cause increased oil consumption and a spark knock during acceleration; the gasket should be replaced.Google+
Car Problem Reports
Dodge Ram Van 2500 Increased Oil Consumption Due to Intake Manifold Plenum Gasket Leak
Dodge Ram Van 2500 Problem
Engine Affected: 5.2L V8
Visitor, 1996 Dodge Ram Van 2500, 5.2L V8, 160,000 mi
Some oil consumption and greatly increased coolant loss due to intake manifold gasket break.