A vacuum leak from the PCV grommet vacuum leak can cause the Check Engine Light to illuminate. The molded rubber hose connections may crack and collapse, causing the vehicle to run roughly. A damaged PCV hose will require replacement.
Car Problem Reports
Lincoln Mark VIII Check Engine Light Due to PCV Grommet Vacuum Leaks
Lincoln Mark VIII Problem
Average Mileage: 97,500 mi (85,000 mi - 110,000 mi)
Visitor, 1994 Lincoln Mark VIII
Check engine light comed on when engine is cold and going up a hill under a load. Does not happen all the time
Check engine light on miss firings