The intake manifold O-ring gaskets commonly leak, causing stalling and poor idle quality; the Check Engine Light will illuminate.Google+
Car Problem Reports
Ford Explorer Sport Trac Vacuum Leak From Intake Manifold O-Ring Gaskets
Ford Explorer Sport Trac Problem
Engine Affected: 4.0L V6
Average Mileage: 93,114 mi (58,000 mi - 165,000 mi)
check engine light on, lean mixture banks 1 an 2. Found leaking hose for the PCV system at top front of engine,near upper raditor hose connection. It is a 90 degree angled 1/2 inch hose 3 x3 inches long. Rubber deteriorated from age. Found 3 more at salvage yard with similar problem. This is on a 4.0 v6 engine, Ford Eplorer, Sport trac, and Ranger that use this motor.
Visitor, 2002 Ford Explorer Sport Trac, 165,000 mi
same as others, not repaired yet.
Visitor, 2002 Ford Explorer Sport Trac, 58,000 mi
Same exact problem, was replaced by dealer for a good sum of money, around $400