Some 2004-2010 Lincoln Navigator vehicles equipped with a 5.4L engine may exhibit an intermittent rattle noise and rough idle when the engine is at operating temperature. The issue is caused by oscillating cam timing. DTCs P0022, P0021, P0340 and/or P0341 may be stored in the PCM.
1. Using the integrated diagnostic system (IDS) or equivalent, monitor cam solenoid duty cycle and cylinder head temperature (CHT) parameter identification (PIDs).
a. Start IDS
b. Select data logger.
c. Select PIDs VCTDC, VCTDC2 and CHT.
2. With the engine idling at normal operating temperature CHT above 200 degrees Fahrenheit, apply the parking brake and hold the service brake pedal firmly with the transmission shifted into D. Raise engine rpm from idle to about 1,500 rpm and release the throttle.
Does the engine exhibit a rattle type noise with a rough idle and are the cam solenoid duty cycle PID values oscillating after rpms return to idle speed? If yes, proceed to Step 3. If not, this bulletin does not apply. Continue with diagnostics.
3. Replace both the left and right variable camshaft timing (VCT) oil control solenoids.
8L3Z-6M280-B………….Variable camshaft timing solenoid
(gasket P/Ns vary depending on cam cover bolt quantity)