2003 Lincoln Aviator how to change spark plugs

Last one back on the right side (standing behind the engine).

Check for Codes & look at all data
Have the spark plugs been changed every 3 years
since the truck was new
Have all the ignition coils failed or been replaced since
2003.
And on & on
Can't be all that hard to get figured out

1) IGNITION timing is late ,adjust the i.timitn to manufacturer specification doesnot matter if you have EI.
2) spark plug are foulde. +wires spark plug test
3) distributo cap is chpped
4) EI module defective and associates components. + ignition coil defective
5) test the scanner +computer for some defective SENSORS too.
God bless you
5)

check for codes...did you use motorcraft plugs...if misfire code check for cracked plug...closed gap...replace coil on cyl with code

The spark plugs are in the cylinder head under the ignition coils, which are under the cover on each rocker cover.

CAUTION! Spark plugs should be loosened 1/4 turn, then compressed air should be used to clear any debris from the spark plug tubes before removing the spark plugs. Failure to do this can result in debris falling into the spark plug holes and entering the combution chambers. This can result in serious damage to the engine.

Yes,sparkplugs could be bad.Also check sparkplug wires.If they havnt been changed in around 60.000 miles, chang them.

The COPS (coils) may have shorted the drivers in the PCM (computer). You should get a misfire code for each cylinder misfiring though.

Slim possibility, but very expensive unless you have a service contract.
LINCOLN: 1999-2004 Navigator
2002-2003 Blackwood
2003-2005 Aviator MERCURY: 2003-2004 Marauder
ISSUE: Some 1999-2004 Navigator, 2002-2003 Blackwood, 2003-2005 Aviator, 2003-2004 Marauder and 2003-2004 Mustang vehicles built before 12/19/2004 equipped with 4.6L 4V/5.4 4V engine may exhibit a runs rough, lacks power, and engine misfire, prompted by a MIL light and DTC codes P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, and P0316.
ACTION: Diagnose engine for engine misfire concern. If diagnostics determine an engine misfire which is characterized by leakage through exhaust valve(s), only replace the affected cylinder head(s).
SERVICE PROCEDURE FOR VEHICLES WITH RUNS ROUGH/MISFIRE CONDITION:

1. Perform relative compression check on all cylinders. If abnormal, check cylinder leakage and actual compression for "low" cylinders refer to Workshop Manual (WSM), Section 303-00.
2. If leakage/compression check indicates a valve train concern, per valve train diagnostics in WSM, Section 303-00, replace cylinder head and cam assembly, pipe plugs and timing chain tensioner, per procedure outlined in WSM, Section 303-01.
3. If cylinder leakage and compression tests are inconclusive, perform misfire diagnostic, per TSB 05-22-8. NOTE: DO NOT TRANSFER SPARK PLUGS. INSTALL NEW SPARK PLUGS IN REPLACEMENT CYLINDER HEAD AND CAM ASSEMBLY. NOTE: THE ENGINE MISFIRE CONCERN IS TYPICALLY EXHIBITED ON THE LEFT HAND CYLINDER HEAD AND RARELY ON THE RIGHT HAND CYLINDER HEAD. UNLESS CONFIRMED, THE RIGHT HAND CYLINDER HEAD SHOULD NOT BE REPLACED AS AN "EXTRA MEASURE" SERVICE PRECAUTION. NOTE: THE REPLACEMENT CYLINDER HEAD WILL NOT IMPROVE OR REDUCE ENGINE HORSEPOWER OR TORQUE ABOVE ADVERTISED LEVELS.
   

Hi! As a first course of action please check the sparkplugs. If the plugs are full of carbon this can cause a rough idle on the car. You will need to clean or replace the plugs if necessary. Hope this helps and thank you for using FixYa!

POSSIBLE CAUSES FOR SPARK PLUGS FOULING OUT. WEAK SPARK IGNITION SYSTEM - STOP UP AIR FILTER - LEAKING FUEL INJECTORS - FAULTY FUEL PRESSURE REGULATOR WITH LEAING DIAPHRAM.

Not spark plugs. Never was.
Bad coils.
Switch the COP Coil for the misfire cyl,and see if 300 code moves with coil.
Does it go into Failsafe or just get the MIL Light on dash?