The check engine light being on is telling you that you have a diagnostic trouble codes stored in the pcm! If we knew what the code is we could have a better chance of telling you what the cause is or at least tell you what diagnostic procedure would be followed at the dealer to find the cause! Most local auto parts stores will connect a scan tool and perform a free code scan for you! This engine has had some issues with the ignition coils, as each spark plug has its own coil, if any of them get water or oil intrusion where they contact the spark plug, it causes the coil to fail when it gets hot! There was a recall on this vehicle for that happening, however it expired in December of 2007, I have attached the customer letter below!
Frank M. Ligon
Service Engineering Operations
Ford Customer Service Division
Ford Motor Company
P.O. Box 1904
Dearborn, Michigan 48121
July 3, 2007
TO: XXXXX XXXXX Ford and Lincoln Mercury Dealers
SUBJECT: Customer Satisfaction Program 07M07
Certain 2003 Model Year Lincoln LS and Ford Thunderbird Vehicles Equipped With 3.9L Engine - Extended Warranty Coverage on Ignition Coil Assemblies and Engine Valve Cover Gaskets
This program extends the warranty coverage of the ignition coils and engine valve cover gaskets to 10 years of service from the warranty start date of the vehicle or 100,000 miles, whichever occurs first. For vehicles that have accumulated more than 100,000 miles, coverage will last until December 31, 2007. Coverage is automatically transferred to subsequent owners.
VEHICLES COVERED BY THIS PROGRAM
Certain 2003 model year Lincoln LS and Ford Thunderbird vehicles equipped with 3.9L engine built at the Wixom Assembly Plant from Job 1 through Job Last. Affected vehicles are identified in OASIS.
REASON FOR PROVIDING EXTENDED WARRANTY COVERAGE
Some of the affected vehicles may experience an engine misfire condition predominantly due to internal breakdown in the coil and lack of adhesion between the epoxy and the coil housing material. These issues may cause the coil to operate at an insufficient voltage level, resulting in ignition coil misfires. In addition, on some of these vehicles, the valve cover gaskets may allow engine oil to enter the spark plug well and cause degradation of the ignition coil boot, resulting in ignition coil misfire. Drivability symptoms associated with an ignition coil misfire include rough running engine, surge or hesitation on acceleration, and/or illumination of the check engine light.
If any of the above mentioned drivability issues are reported on an affected vehicle, dealers are to identify any engine cylinder that is misfiring and perform an ignition coil stress test on the affected cylinders. If the coil fails the stress test, dealers are to replace the ignition coil and associated spark plug. If any coil boot is contaminated with engine oil, dealers are to contact the Special Service Support Center for prior approval to replace the contaminated ignition coil boot, the associated spark plug and install a new valve cover gasket set. This service will be performed on affected vehicles at no charge to the vehicle owner.
This extended warranty coverage program only applies to ignition coil assemblies and valve cover gaskets. During diagnosis, if other concerns or DTC's are found, they will not be covered under this program and are the responsibility of the vehicle owner, if the vehicle has exceeded the time or mileage limits of all other warranty coverages (NVLM/Emissions/Extended/etc.). Owners who received letters announcing 07M07, and who bring their vehicles into the dealership because of an engine misfire condition, should be advised that this program only covers the cost of repairs related to defective ignition coils or valve cover gaskets that are allowing oil to enter the coil on plug wells.
Other repairs are not covered by this program.
COILS CONTAMINATED WITH WATER: If any coils are contaminated with water, dealers should perform Field Service Action 07N09 after performing this program (07M07).