How to Change Spark Plugs for a Ford F-150 4.6L Engine

How to Change Spark Plugs for a Ford F-150 4.6L Engine
Written by Jeff Glucker

One of the most critical elements in engine operation is the spark plug. By igniting the working mixture, they contribute to engine operation. In most cases, the number of spark plugs corresponds to the number of the engine cylinders, but there are exceptions, too.

If there is a problem with the spark plugs, the engine starts to run under critical loads, even if just one of the plugs fails. The spark plug change interval is shown in the service card of the vehicle manufacturer, but if the engine is not running smoothly, the spark plugs have to be replaced. If you have noticed any misfire under load, hard/rough starts, poor fuel economy, or inadequate throttle response – you need to take measures immediately.

The main task of spark plugs is to be able to carry the highest loads. As with oil, expensive and high-quality consumables will last much longer, in contrast to cheaper counterparts. In the event of a malfunction in the engine system of the vehicle, under no circumstances should their replacement be postponed. Often the problem with the plugs leads to the Check Engine lights. The timely replacement of spark plugs in the Ford F-150 will significantly increase fuel economy, save your money and nerves.

Before we get into the installation process, we strongly recommend you not to risk your engine unless you know what you’re doing. Replacing the spark plugs by yourself is never a good idea if you’re not sure how to remove them from the cylinders safely. Experts in certified auto repair shops use specialized equipment that allows doing the job efficiently and quickly.

But if you feel you are ready, let’s move on!

What You Will Need

  1. Latest Ford PZH 1F spark plug modifications, or Motorcraft SP-514, or Motorcraft Spark Plug SP546 Set Of 8.
  2. You can also choose: Ford Racing M-12405-3V0 3-Valve Range Zero Spark Plug for 4.6L Engine, (Pack of 8), For 1997-2000 4.6L V8 – Motorcraft SP-413 Spark Plug or Motorcraft SP-432 Spark Plug For 2009-2010 4.6L V8 – Motorcraft SP-509 SPARK PLUG, For 2001-2008 4.6L V8 – Pack of 8 Genuine Motorcraft Spark Plug SP-493 AGSF32PM
  3. Motorcraft XL-2 Anti-Seize Lubricant или HUSKEY 684 Nickel Anti-Seize.
  4. Lisle (LIS65600) Broken Spark Plug Remover for Ford Triton 3 Valve Engines.
  5. You can also use this plug removal tool from Ford Rotunda 303-1203.

The process of replacing the spark plugs on the 4.6L engine may be quite challenging. You can thank Ford for that. Initially, the problem has long been recognized by the manufacturer, which is trying to solve the problem by producing new spark plugs. The location is hard to access, and there’s a high possibility you will strip the spark plug threads. However, once you have the right tools at hand, the process can get much more straightforward and will take you a few hours at first try. Once you figure everything out, you will have no problems with repeating the whole process much faster.

We recommend checking your ignition coils first. Unless they are new or in excellent condition, replacing them with these, for example, is a wise move since you have them off anyway. 

Easy Replacement

  1. The engine must be at room temperature (not warm) before you start taking out the plugs. This will reduce the risk of breaking all of them at once (lol). At least that’s what the official Ford TSB # 08-07-06 says. 
  2. Spray in a little Motorcraft PM2 carb cleaner, or PM3, or the Johnsen’s 4641NC-12PK Non-VOC Compliant Carburetor Cleaner Spray, and leave it for 15 minutes.
  3. Carefully unscrew the plug with little effort by swinging it from side to side.

Not That Easy Replacement

Every spark plug is accessed through the cylinder head’s opening, which is a few inches lower every separate ignition coil. Are you ready for a blind operation? Well, you better be ready. Because… When the sh*t goes down, you better be reeaaaadyyyyyy! The thing is that for most cylinders, you will not be able to see the spark plug.

  • Gently disconnect the negative battery terminal cable. You have to do that every time you are working with anything electrical in your truck. Use an 8mm socket.
  • Grab some compressed air device and spray it all around the ignition coils so you can clear the debris so that it doesn’t fall into the engine when you remove the spark plugs. Go down good in there and make sure you get rid of all the debris completely.
  • Unplug the electrical connector from the ignition coil. It’s pretty easy. There’s a safety on the bottom there, so you just push that up and walk the connector back.
  • Remove the bolt that holds the ignition coil into the intake manifold. Use a 7mm socket to remove the bolt. Be careful not to lose the bolt in the engine bay.
  • Remove the ignition coil by wiggling it, bending it out of the way of the fuel rail, maneuver it toward you and pull it straight up firmly with even pressure not to shred the boot. The rubber boot inside the spark plug socket will secure the spark plug, so it comes out when the socket is removed. Once you take it out, remember how it was kinked inward toward the center of the block, so as not to put it back the wrong way later. Don’t be scared to separate the insulator boot from the rest of the coil – it’s totally OK.
  • Take a 5/8 spark plug socket (1997 – 2003 model years) or 9/16″ (2004+ model years) and install it down there on the plug. Make sure that the spark plug socket sits firmly on the plug nut before attaching the ratchet not to strip the hex head. Loosen it a little (quarter turn). Then apply a little carb cleaner spray down there and let it soak into the threads, so the spark plug comes out easier (15 minutes). Then disconnect your ratchet and finish unscrewing by controlling the extension manually.
  • Make sure to eliminate any debris from the cylinder head’s bore where the spark plug sits. Blow it out with compressed air. Any dirt may enter the cylinder when the spark plug is pulled.
  • Now there are only seven more spark plugs left!
  • Make sure you verify the gap of the replacement spark plug (refer to your manual for the proper gap and set it using a feeler gauge or find a video on YouTube on how to do that, the gap will vary with the model year). Each engine has a unique specification for its spark plug gaps. That’s the space between the electrodes that the spark jumps across to ignite the gas inside the cylinder. You can use the hook on the gauge to open the gap a little if you need it. In case it’s wide enough, carefully press the electrode down on a non-marrying surface until it meets specifications.
  • Apply some dielectric grease (e.g., Permatex 22058) to the tip of the ignition coil. Take a screwdriver to shove it down towards the spring, make sure you get an even distribution of the grease, or simply put it on the spark plug without any preparation – it will get evenly distributed anyway.
  • Apply a light coating of the anti-seize (e.g., Permatex 77134) to the threads so the next time you remove the spark plugs they come out easier. Make sure you don’t touch it with your fingers while you are applying the anti-seize because you don’t want to make any mess.
  • Install the new spark plug. Place it into the spark plug socket without touching the strap, bumping it or bending in any way. Be extra careful when inserting the spark plug. Don’t contact any of the walls as the spark plug goes in the well. Do it manually to feel that everything goes right, without any cross-threading. Doing it by hand is easier. No power tool should be used here. Tighten it up a little bit (do not overtighten) and snug up the plug. Medium tightness is the way to go.
  • Take your torque wrench and set it to 13 foot-pounds, so it’s not too tight.
  • Put the new ignition coil on. Insert it in and make sure it’s seated. Check if it’s lined up with the bolt hole. It’s 62 inch-pounds, so we hope you have a torque wrench that can go down that low. Replace the ignition coil bolt and tighten it up without any excessive force.
  • Take your electrical connector and push it on the ignition coil.
  • Do the same for all other spark plugs.

About the author

Jeff Glucker

Jeff Glucker is a longtime editor and columnist at MechanicFAQ.com. He’s a proud Delaware native and currently lives in Wilmington. When he’s not writing about cars, he’s driving them. And when he’s not driving them, he’s probably doing something else like spending time with his wife or yelling on his children because you need to do that too. You can follow him on Twitter @JGlucker

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