What causes cylinder 3 misfire on my 2005 lincoln avatior. already replaced plugs and coil. what else could it be?

The coil sits on top of the number 3 spark plug.

https://www.google.com/search?q=2011+lincoln+mkx+coil+pack

https://lincolnmkzforum.com/topic/706-asap-please-anyone-know-the-cylinder-numbers/

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Broken valve spring or burned valve

315 is a bad coil on #5 cylinder(could be bad wire to coil). 306 is #6 cylinder misfire(plug,boot or wires). 300 is random misfire, caused from #5 and #6 misfiring. Time for a tune up.

change all plugs with proper ones - they are picky for some reason - do not change number or brand from original - coils were probably ok, - get some injector cleaner and run through it but check for exhaust leak at e g r tube - is a common over looked cause of misfire - a thing to keep in mind is misfire isn't always spark issue. hope I was of some help

If you already replaced all those thing there is only 2 things left that could be causing this problem one(you don't what it to be this one) low compression on cylinder 3 or the cheap fix, the coil pack, I would check the coil pack before checking compression.

There are a few things that can cause an engine misfire and hesitation. Does your van have a CoP ignition system? (Separate ignition coils for each spark plug) Or coil pack? You may have bad ignition coil(s); that would cause a misfire. If you have a dirty/clogged/leaky fuel injector for cylinder 3, that could also cause a misfire condition. When you replaced all the spark plugs, did you look at the plug from cylinder 3? Did they all look the same? Sometimes you can get clues to what is going on in your cylinder by how the spark plug looks: if it's white or glazed you are running too lean and could indicate fuel injection problem, if it's got burnt oil on it and it's sludgy you may have a leaky gasket or worn piston ring that is letting oil up into the combustion chamber and fouling the plug, causing a misfire. If your check engine light comes back on and it's the same misfire code, have the coil for cylinder 3 checked to see if it's weak or bad. Or you can do a home remedy check and swap a known good ignition coil from another cylinder to 3, reset the code, and see if the misfire moves to another cylinder. If it does, you know the coil is bad. You can pick up an ignition coil for pretty cheap on the internet ($30-$70) if that's the problem and they're simple to install (a pain if they're on a cylinder that's under the intake manifold, but just because you have to unbolt a bunch of stuff to get to it...time consuming but not too difficult). I have a 2001 Mazda Tribute and had a couple of ignition coils go bad, causing misfires. This seems to be a semi-common problem for early 2000's Mazdas.

simply swap out one injector for another (I simply say if you there already just replace the injector...its a possibility that it is a bad or plugged up fuel injector. on number 4 cylinder. if spark and fuel are ok, its the injector doing this. good-day !

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.
   

Replace the coil pack once more. I went through 2 new ones on my f150 on one cylinder. One worked, the other didn't (both new off the shelf). Condensation build up in the boot caused mine to misfire. Anytime you replace a coil pack, squirt a little silicone grease inside. This will prevent condensation from hitting your plug. Fords are notorius for this problem, especially if you live in a humid area. Also, make sure and clear the codes after you make the repair.

Hello I need a help.
I have 1999 lincoln town car 4.6L V8.They have check engine light on. P 0303 cylinder 3 missfire.
I was changed spark plugs,fuel filter. check compression test 150psi. fuel pressuer 50.
swiching cylinder 1 to 3 fuel injector and coil. but they still have engine code