Some 2010-2011 Ford Flex vehicles equipped with a 3.5L gasoline turbocharged direct injected engine may exhibit rough running, hesitation, shuddering, etc., with DTCs P0300, P0301, P0302, P0303, P0304, P0305, P0306 or P0316.
1. Determine the engine build date (refer to the workshop manual section 303-01). If the engine build date is on or before Aug. 2, 2010, proceed to Step 2. If the build date is after Aug. 2, 2010, proceed to Step 5.
2. Retrieve DTCs to determine which cylinder(s) have misfired.
3. Remove the spark plug of the affected cylinder(s).
4. Check the spark plug(s) for broken ceramic. If the spark plug has broken ceramic or the P/N is CYFS-12F-3, replace all six spark plugs. If the spark plug(s) do not have broken ceramic, and the P/N is CYFS-12Y-3, do not replace the spark plug(s) and proceed to Step 6.
5. Determine the vehicle build date. If the vehicle was built on or before Oct. 27, 2010, proceed to Step 6. If the vehicle was built after Oct. 27, 2010, do not continue with this bulletin. Refer to the powertrain control/emissions diagnosis manual for normal diagnostics.
6. Reprogram the PCM to the latest calibration using IDS release 72.03 and higher. Calibration files may be obtained at www.motorcraft.com.