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Acura TL 2004-2008: How to Replace Ignition Coils and Spark Plugs

A P0306 code is a misfire on cylinder #6. This would most probably mean a bad coil or spark plug; though, it could be other things as well. If you are in need, changing one of these out is fairly easy. It just takes the tools and little bit of patience. Even if you are just replacing spark plugs at the regular 105k mile interval, getting this job done will save you some fuel and some possible headaches down the road. Read through the article to see just how easy it is to complete this job.

By Paul Johnson - April 29, 2016

This article applies to the Acura TL (2004-2008).

Changing spark plugs on the TL doesn't happen very often, that's for sure. At 105k mile interval, most people will probably change them once during ownership. Needless to say, changing them out on time is important, for the only reason of better fuel economy, as the plug gets worn out and the computer can no longer adjust the spark due to the wear. About the only time you may not want to complete this job yourself is if you don't have the tools and have no plan on buying yourself some. This job really doesn't take much time to complete and can be well worth your time to do it yourself.

Acura TL 2004-2008: How to Replace Ignition Coils and Spark Plugs

Materials Needed

  • Metric tool set (3/8" drive set)
  • (2) 3" extensions
  • Universal joint
  • 5/8" spark plug socket
  • 6mm Allen wrench
  • Torque wrench
  • Flat head screwdriver
  • Anti-seize compound
  • Dielectric grease
  • Long needle nose pliers

Step 1 – Remove engine covers

Raise the hood. If so equipped, remove the engine covers. Start with the passenger side near the fender. Move around the back of the engine bay and to the right (Figure 1). The long skinny one near the cowl has some clips which can provide a little difficulty, but all clips just pull out with a little firm persuasion. Remove the intake manifold cover by turning the three plastic "bolts" at the front of the engine 90°.

Remove Covers Spark Plug Removal honda acura j32 j35 j37 v6 tl tsx tlx mdx rdx rlx spark plug ignition coil replace remove how to
Figure 1. Remove engine covers.

Step 2 – Remove strut tower brace

Note

If only replacing a coil from cylinders 4, 5, or 6, this step is not necessary.

To ease the removal of the rear coils and/or spark plugs (cylinders 1, 2, and 3), remove the strut tower brace. This is not absolutely necessary, but makes this job a ton easier. There are three 12mm nuts (green arrows in Figure 2) and one 10mm bolt (red arrow ) on each end of the brace which need to be removed. The strut tower brace should then pull away easily.

Strut Bar Removal Spark Plug Removal honda acura j32 j35 j37 v6 tl tsx tlx mdx rdx rlx spark plug ignition coil replace remove how to
Figure 2. Strut tower brace removal.

Step 3 – Remove (and replace) coil

Remove the wiring harness from the coil to be removed by pressing the tab and wiggling the connector free. Using the 6mm Allen wrench, loosen then remove the Allen head bolt attaching the coil to the head. Slightly twist and pull the coil to remove it from the head. If to be reused, place the coil aside in a safe place to avoid accidental damage. Perform this for every coil to be removed. To replace, place the coil back into the head, engaging the spark plug fully. Screw the Allen head bolt back into place to secure the coil, then tighten snugly, but do not over-tighten. Refasten the wiring harness to the coil.

Coil Removal Spark Plug Removal honda acura j32 j35 j37 v6 tl tsx tlx mdx rdx rlx spark plug ignition coil replace remove how to
Figure 3. Coil removal.

Pro Tip

An easy test to see if the coil is at fault is to switch its position to a different cylinder. If the misfire persists at the same cylinder, it's not the coil. If it follows to the new cylinder, plan on replacement.

Step 4 – Replace plugs

On the front three cylinders, assemble the spark plug socket, extensions, and ratchet. Place the socket down into the spark plug hole to engage the spark plug (Figure 4). If your spark plug socket no longer has the rubber insert, plan on having a set of long needle nose pliers handy to remove the plug when it has been completely backed out of the threads. One with a small bend at the tip comes in plenty handy, as it makes it much easier to grab the spark plug. For the back three plugs, putting a universal joint between the two extensions will greatly ease in getting the socket and extensions into the hole. It may be difficult to remove the spark plug without the rubber grommet in the spark plug wrench on the rear cylinders, so be wary.

Spark Plug Removal honda acura j32 j35 j37 v6 tl tsx tlx mdx rdx rlx spark plug ignition coil replace remove how to
Figure 4. Spark plug removal.

When installing the new plugs, use a small amount of anti-seize compound on the threads. Gently thread them into the head using just the socket and extension. Tighten until hand-tight. Using a torque wrench, tighten the spark plugs to 13 lb-ft (156 in-lbs). Do not over-tighten, as this can strip the threads out of the head. Use some dielectric grease in the coil to plug boot to ensure a secure and sealed connection.

Step 5 – Re-installation

After installing all necessary parts, start the vehicle to ensure proper operation. When satisfied with the job, replace the engine covers in the reverse order of disassembly. Shut the hood and call it a day.

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