1999 Ford E-150 Spark Plug Replacement Guide

There’s a likely probability you will need to replace your worn out spark plugs several times while you own a a 1999 Ford E-150. Spark plugs are one of the most critical components inside your engine as they start the entire combustion process that starts and keeps your engine running for many thousands of miles. Similar to most engine components, spark plugs experience wear over time and eventually need replacement, but fortunately this is a repair you can do yourself. Odds are, if you’ve found yourself here, you have no idea how to do that, or maybe you’d just like to know what kind of spark plugs you need to buy. The complete process of changing your spark plugs should take roughly 20-45 minutes. This article will go over everything you’ll need to know about your Ford E-150’s spark plugs, whether you need some baseline information or a full, step-by-step guide to performing a spark plug change.

Correct spark plugs on a 1999 Ford E-150

Recommended 4.6L V8 1999 Ford E-150 Spark Plugs

4.6L V8: Autolite 104-4PK Copper Resistor Spark Plug, Pack of 4
For the 4.6L V8 1999 Ford E-150, you can use AUTOLITE 104 spark plugs. As this 4.6L V8 features 8 cylinders, ensure that you purchase at least 8 spark plugs in total.

Recommended 5.4L V8 1999 Ford E-150 Spark Plugs

5.4L V8: Autolite 103-4PK Copper Resistor Spark Plug, 4 Pack
For the 5.4L V8 1999 Ford E-150, you can use AUTOLITE 103 spark plugs. As this 5.4L V8 features 8 cylinders, ensure that you purchase at least 8 spark plugs in total.

Recommended 4.2L V6 1999 Ford E-150 Spark Plugs

4.2L V6: Autolite 5144 Copper Resistor Spark Plug, Pack of 1
For the 4.2L V6 1999 Ford E-150, you can use AUTOLITE 5144 spark plugs. As this 4.2L V6 features 6 cylinders, ensure that you purchase at least 6 spark plugs in total.

These spark plugs are an exact fit for their respective engines and will match the required specifications. Make certain that you purchase the correct number of spark plugs for your engine corresponding to the number of cylinders. Often, manufacturers will bundle spark plugs in quantities that make it impossible to buy the exact amount you need for your engine. In this case, it is a good idea to purchase enough for your next two spark plug changes just so you will always have a new set ready to go. We always try to recommend the best possible spark plugs for the money, and these spark plugs are either a factory recomendation or an equivalent replacement available in today’s market at a reasonable price.

How often should I change my spark plugs?

As a general recommendation, it is advised that you replace spark plugs once every 20,000 to 40,000 miles. Of course, please make sure to check your owner’s manual to determine the exact interval determined by Ford for the 1999 E-150. Of course, if you drive your vehicle more aggressively or own a Ford E-150 with some modifications, you may want to consider changing your spark plugs closer to the 20,000 miles end of that spectrum.

However, there are also classic signs of a car that may potentially need a spark plug replacement early, such as:

  • Engine misfiring
  • Problems starting your engine
  • Rough idle

As a quick note, keep in mind that this list is absolutely not comprehensive, and these problems on their own do not necessarily point to the spark plugs being the solitary culprit. However, the best way to prevent any issues with your vehicle is to take care of it with regular maintenance, and you are definitely doing so with the responsible decision to replace your 1999 Ford E-150’s spark plugs on a regular basis.

Changing spark plugs on a 1999 Ford E-150

This is a process you can do on your own with some commonplace garage tools. Of course, consult your owner’s manual, as well as a factory service manual (FSM for short) or an equivalent Haynes or Chiltons manual. The video shown below does a good job of outlining the process.

Helpful Tools

A set of spark plug sockets is a must have. Certain spark plugs and engines make this job nearly imposible without one
As noted before, you should be able to accomplish a spark plug change with some regular tools you likely already have. However, there are a few tools that are specific to this job that you may not have, and we also want to recommend some commonplace tools that you should definitely have in your toolbox if you do not already.

  • A torque wrench is a essential tool to have in your toolbox. You will want to check your factory service manual to determine the correct torque rating to use when putting in the new spark plugs for your 1999 Ford E-150 to be sure they are installed properly.
  • A spark plug tester – this is definitely a niche tool, but it can save you a ton of time. Although we’ve discussed spark plug replacement being a good thing to replace regularly and not just when issues occur, you may also be replacing your spark plugs because of a problem. This tool can help you diagnose the exact problem.
  • A set of spark plug sockets – These come in extremely handy because many standard sockets are not deep enough for spark plugs. Additionally, some spark plug holes are a bit smaller, so it requires a thinner wall like the one featured in the product here to fit. The linked product also features a magnet to keep a good hold of the spark plug so you do not drop it into your engine bay!
  • A spark plug gap tool. This allows you to check the gap of your spark plugs and change it if necessary. Most plugs will come pregapped, but if not, you should definitely have one of these.

Tips for changing spark plugs on your 1999 Ford E-150

It is a great idea to have some dielectric grease handy.
Ensure you watch the video above before you attempt to repair the spark plugs on your 1999 Ford E-150, as well as review your factory service manual. Also, see the tips included below here to help you as you perform this repair.

  • Your engine should be completely COLD before you replace your spark plugs. You should wait at least 30 minutes after your engine has been running before attempting to replace the spark plugs on your 1999 Ford E-150
  • The most important thing is to avoid overtightening the plugs or worse, cracking them due to overtightenting. Use a torque wrench capable of lower, more precise torque ratings to be sure that you don’t make this mistake.
  • Note that this is not official advice as many spark plug manufacturers advise against the use of anti-seize. However, I have heard from numerous old-school mechanics that they always apply a small amount of anti-seize to the threads of their spark plugs, especially on older vehicles.
  • First, disconnect the negative terminal of your battery. You should always disconnect the battery anytime you work on the electrical system of your Ford E-150 or any other vehicle.
  • It isn’t a bad idea to use dielectric grease when installing new spark plugs. You can apply a small amount to the inside of the boot and the ceramic part of your spark plugs. It prevents voltage leak and helps avoid the misfortune of the boot fusing to the spark plug over time.

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