Owners of other Honda or Acura vehicles with "K" series motors such as the Civic, CR-V, Integra, RSX, RDX, TSX, Odyssey, and Element may also find these DIY instructions to be helpful.

A few compatible replacement spark plugs include the following with their part numbers: Denso 3461 (SXU22HCR11S), NGK 5787, Pulstar Pulse gg1i, Champion 9407 (RER8ZWYCB4), Bosch (9619) YR6SII330X, Denso (5356) IXUH22I, Honda 12290-R40-A02, and Autolite XP5702.

The tools required to complete this procedure include a 10mm socket with 1/4" drive ratchet, a 5/8" spark plug socket with a 3/8" drive ratchet, a 6" extension bar, dielectric grease and anti-seize lubricant (optional).

Pop open the hood and locate the rectangular black plastic spark plug access cover on the top of the engine just past the dipstick and oil filler cap.

Remove the four bolts on the cover with the 10mm socket and a 1/4" drive ratchet.

Set the bolts aside in a safe place.

Below the cover, you'll see the four black/grey ignition coils with their power plugs.

Remove the bolt holding the spark plug ignition coil in place with a 10mm socket and ratcheting wrench by turning it counter clockwise. Set the bolt aside in a safe place.

I'd recommend working on one spark plug at a time to further reduce the risk of having something drop down in to the engine.

Rotate the ignition coil back and forth a few times to ensure that the rubber dust boot at the end of the coil is not stuck to the top of the spark plug.

Lift the ignition coil straight out of the spark plug well.

The spark plug socket should have a rubber insert or magnet to securely hold the spark plug.

Carefully lower the spark plug socket down in to the well and attach it to the top of the spark plug.

Gently loosen the old spark plug by turning the wrench counter clockwise.

If the spark plug won't turn, spray in some penetrating oil such as PB Blaster, Liquid Wrench or Kano Kroil and wait 15-30 minutes or more before trying again. If you don't have any penetrating oil, try spraying in some WD-40 lubricant or just warm up the engine for a few minutes to expand the metal engine block.

Once the spark plug is loose, detach the ratcheting wrench from the extension bar and spin out the spark plug the rest of the way by hand.

Carefully lift the old spark plug straight out of the well.

The OEM iridium tipped spark plugs on this 2009 Honda Accord LX Premium sedan are Denso 3461 or "SXU22HCR11S".

If the end of the old spark plug looks ashy white, the plugs may have been exposed to high temperatures such as engine overheating or they are the incorrect heat range for your driving conditions and/or environment.

If the old spark plugs are dark grey or covered in black soot, the engine may be burning oil and should be checked out by a professional.

An optional step is to apply a tiny amount of anti-seize lubricant to the upper threads of the new spark plug. This will make the plugs easier to remove if they are not replaced again for another 100,000 miles. Do not get any anti-seize on the electrode at the bottom of the new spark plug. Some spark plug manufacturers advise against using anti-seize.

Insert the new spark plug in to the socket and carefully lower it down in to the well without hitting the electrode tip. Spin the new spark plug in by hand in the clockwise direction until it makes contact with the engine block.

Attach the ratcheting wrench to the extension bar and tighten the new spark plug to just barely past the point when you feel the crush washer collapse.

If you applied anti-seize lubricant to the threads, less force will be necessary to tighten the plugs. Do not over tighten the plugs to avoid cracking the ceramic part of the plug or stripping the aluminum threads in the cylinder head.

Double check that the new spark plugs are tight before moving on to the next steps.

Apply a small amount of dielectric grease to the opening of the rubber dust boot at the bottom of the ignition coil.

This will help prevent the ignition coil from becoming stuck to the tip of the new spark plug and keep out any moisture.

Lower the ignition coil down over the tip of the new spark plug and rotate it a few times to spread the dielectric grease.

Re-insert the ignition coil bolt and tighten it with the 10mm socket and ratcheting wrench.

Start up the engine and listen for any strange sounds that may indicate a problem.

Be sure to record the spark plug change in your vehicle's service records.

For more, check out my other 2008-2012 Honda Accord Repair & Maintenance Guides.