Spark Plugs and Wires
Ford Expedition XLT

1998 Ford Expedition your check engine light went on and you placed it on the computer and it said there was a misfire you replaced the 2 coils and 6 spark plugs and wires It's still missing and doing?

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2008-03-09 07:01:15

When you replace plugs and wire or coil packs always do them all

at ones... How to Change Spark Plugs on 4.6 & 5.4 Liter By Dave

West I've replaced plugs on quite a few 5.4Ls now (the 4.6L with

plug wires is similar) and once you've done a set they really are

not as bad as they look. Contrary to what some people will say, you

don't have to remove the fuel rails. The Coil on Plug (COP)

assemblies will come out past the fuel rail. I take an old piece of

seat foam and put it on top of the radiator support to the engine

to allow me to lay on it without hurting my tummy. It makes the job

way less painful. Start by removing the cover over the throttle

body (the black plastic cover that says "5.4" on it). There are

three 10mm head bolts that hold it on. Next remove the air intake

tube from the throttle body to the air filter housing. You loosen

the hose clamps at either end of it; disconnect the connector on

the AT (about half way up the air intake hose), the pull out the

small hoses that go into the air intake tube near the throttle

body. Next remove the brace from the power steering reservoir to

thermostat housing. There are three 8mm or 5/16" head screws that

hold it on. Now you should be able to see the COPs. To remove the

COPs you can use a 7mm or 9/32" wrench or nut driver or socket,

extension and ratchet or all of the above. If you turn the fuel

injectors to the side it will give you more room to work with the

COPs. Unplug the connector on each COP by pressing the tab in and

pulling on the connector. After you're done that just twist and

pull the COPs out. A couple of the COPs on the driver's side and #4

on the passenger's side are a bit hard to get at but with some

patience they will come out. After you've removed the COPs take a

blow gun and blow out the spark plug holes. Don't be surprised if

there is rust and junk in them. Next you can actually remove the

plugs. Use a combination of extensions, swivels (universal joints),

sockets and ratchets to get at them. Whatever works best for you is

good. On the harder ones to get at I usually use a socket with a 4"

extension, then a swivel, then a long extension, then the ratchet.

The plugs are way down in the hole which is why I use the extension

then the swivel. The swivel makes it easier to clear the firewall.

Set the gap on the new plugs to whatever it says on your emissions

decal on the radiator support....usually .052-.056". Apply a small

amount of anti-seize to the threads only on the spark plug. You can

use a piece of vacuum hose or fuel hose over the end of the plug to

get it started in the hole. Carefully start the plugs in their

holes. If you can't get them most of the way in by hand with the

hose take a look and see why not. Cross threaded plug threads are

no fun! The plugs are to be tightened to 13 lb-ft. which is just

hand tight with a short ratchet. Don't over tighten them! The

threads in the aluminum heads have enough problems as it is. After

that just put everything back together in reverse order. Apply some

dielectric grease to the plug boots as well to help seal them. I've

done enough of these that I can replace the plugs in approximately

45 minutes but don't be surprised if the first time you do it takes

a few hours.

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