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Ford Mustang Spark Plugs Replacement Guide
How to change the spark plugs in a 6th generation 2015 to 2022 Ford Mustang with the EcoBoost 2.3L I4 engine.

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2019 Mustang 2.3L I4
Loosen Counterclockwise
Remove Front Right Nut
This automotive maintenance tutorial was specifically written to assist owners of the S550 sixth generation 2015, 2016, 2017, 2018, 2019, 2020, 2021 and 2022 Ford Mustang equipped with the EcoBoost 2.3 liter turbocharged inline four cylinder engine in checking or changing the spark plugs. (The procedure should be similar for the 5.0L V8, 5.2L V8 and 3.7L V6 engines.)

(The 7th generation S650 Ford Mustang is supposed to be released in 2022 as a 2023 model year vehicle.)

Owners of other Ford and Lincoln vehicles such as the Fusion, Taurus, Escape, EcoSport, Flex, Expedition, Bronco, Ranger, Transit, F-150, C-Max, Fiesta, Focus, Edge, MKZ, Continental, Corsair, Nautilus, Aviator and Navigator may also find these DIY instructions to be helpful.

The OEM (original equipment manufacturer) Ford spark plug part number is FoMoCo CYFS-12Y-PCT (also known as CYFS12YPCT).

A few compatible replacement aftermarket spark plugs for the EcoBoost 2.3L turbo I4 engine with their part numbers are as follows: Denso (4719) ITV20TT, E3 E3.74, Denso (5339) ITV20 and Pulstar EF1H10.

The tools and other items needed to complete this procedure include an 8mm socket with a 1/4" drive ratchet, a deep well 10mm socket with a 3/8" drive ratchet, a deep well 8mm socket or an 8mm wrench, a 5/8" spark plug socket, an extension bar and a tube of dielectric grease.

The first two steps are to open the hood and then locate the four fasteners on the top of the plastic engine cover.

Remove the nut on the front right of the engine cover by turning it in the counterclockwise direction with a deep well 10mm socket and a 1/4" or 3/8" drive ratchet.

Set the 10mm nut aside in a safe place.


Remove Rear Left Nut
Rear Left Nut Removed
Remove Front Left Bolt
Next, remove the other 10mm nut located at the rear left corner of the plastic engine cover by turning it in the counterclockwise direction.

Set the nut aside with the other 10mm nut.

Remove the black metal bolt at the front left of the cover by turning it in the counterclockwise direction with an 8mm socket and a 1/4" drive ratchet.

Front Left Bolt Removed
Remove Rear Right Bolt
Rear Right Bolt Removed
Remove the black metal bolt at the rear right corner of the engine cover by turning it in the counterclockwise direction with the 8mm socket and a 1/4" drive ratchet.

Set the two 8mm bolts aside with the two 10mm nuts.

Two Nuts & Two Bolts
2015-2022-Ford-Mustang-Spark-Plugs-Replacement-Guide-011 2015-2022-Ford-Mustang-Spark-Plugs-Replacement-Guide-012
Pull Off Engine Cover
Carefully lift the plastic cover off the top of the engine.

Set the cover aside in a safe place.

Engine Cover Removed
Top of Engine Exposed
Ignition Coil
To help reduce the risk of having debris fall down into the spark plug well, clean off the top of the engine with a wet/dry shop vacuum or use an air compressor.

I also recommend only checking or changing one spark plug at a time to help further reduce the chance of having a foreign object fall down into the cylinder block.

Slide Out White Lock Tab
Push In Release Button
Power Plug Removed
Gently slide back the white plastic locking tab away from the ignition coil (towards the left / driver side of the car).

Push in the release tab on the electrical connector before sliding it straight off the base of the ignition coil.

Loosen Counterclockwise
Spin Out Ignition Coil Bolt
Ignition Coil Bolt Removed
Loosen the single black metal bolt on the ignition coil by turning it in the counterclockwise direction with a deep well 8mm socket and a 1/4" drive ratchet or use an 8mm wrench.

Set the 8mm bolt aside in a safe place.

Lift Out Ignition Coil
FoMoCo Ignition Coil
Spark Plug In Well
Rotate the ignition coil back and forth a few times to make sure the rubber dust boot is not stuck or "frozen" to the top of the old spark plug.

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

If you have a CEL (check engine light) or SES (service engine soon) warning indicator light on your Mustang's gauge cluster, use an OBDII scanner (also known as an "OBD2 scan tool") to check for an ignition coil related DTC (diagnostic trouble code) such as P0350, P0351, P0352, P0353 and P0354.

The OEM (original equipment manufacturer) Ford ignition coil part number is FoMoCo CM5E-12A366-BC (also known as CM5E12A366BC DQ3NA B1881401362).

Some of the most common symptoms of a failing or faulty ignition coil include misfiring, stalling, reduced fuel economy (lower MPG), backfiring, rough idling, loss of power and the engine won't start.

Spark Plug Socket
Loosen Counterclockwise
Spin Out Old Spark Plug
Attach the 5/8" spark plug socket to the long extension bar and the 3/8" drive ratchet.

I always use a piece of electrical tape to attach the spark plug socket to the extension bar to help prevent it from popping off and becoming stuck down at the bottom of the well.

Loosen the old spark plug by turning it in the counterclockwise direction.

If you have trouble loosening a stuck or stubborn rusted old spark plug, try spraying a very small amount of penetrating oil down into the well.

Allow the penetrating oil to seep down into the threads and loosen any corrosion for at least 15 minutes.

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

Lift Out Old Spark Plug
Inspect OEM Spark Plug
Empty Spark Plug Well

Lift the old spark plug out of the well and pull it out of the socket.

Inspect the old spark plug for any wear or deposits.

If the old plug appears to be burnt or covered in soot or oily sludge, the engine may be burning oil and it should be inspected by a professional mechanic.

If the electrode tip on the old plug appears to be burnt or covered in white ashy powder, the engine might have been subjected to overheating.

You may need to choose a spark plug with a different "heat range" (colder or hotter) for your area's climate or your unique driving conditions.

If you have a spark plug gap gauge tool, check the gap on the new spark plug to make sure it matches the specification listed on the box.

Spin In New Spark Plug
Tighten Clockwise
Apply Dielectric Grease
Push the new spark plug into the socket.

Your socket should have a rubber insert or a magnet to securely hold the spark plug securely in place.

Carefully lower the new spark plug down into the well. Try to avoid hitting the electrode tip against the sides of the spark plug well or the cylinder head.

Spin in the new spark plug by hand until it makes contact with the top of the cylinder head.

Attach the 3/8" ratchet and continue tightening the new spark plug to a fraction of a turn past finger tight.

If you are installing a new spark plug, you may feel the new crush washer collapse.

If you are re-installing the old spark plug after checking it, just tighten it to a small fraction of a turn past finger tight.

If you have a very sensitive and reliable torque wrench, the service manual torque specification for the OEM Motorcraft spark plugs is 12 lb-ft for dry and clean spark plugs.

If you insist on using anti-seize lubricant grease, you may need to tighten them to a higher torque setting of 13 to 15 lb-ft.

Some spark plug manufacturers include torque specifications for their spark plugs. Be sure to check the manufacturer's specification on their website.

Most spark plug manufacturers recommend that you do NOT use anti-seize grease since it can easily lead to over tightening.

Try to avoid over tightening the new spark plug to prevent from cracking the ceramic or damaging the aluminum threads.

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

The dielectric grease will help keep out moisture and debris to insure a reliable electrical connection.

Lower In Ignition Coil
Line Up Bolt Holes
Re-Insert Black Bolt
Carefully lower the ignition coil down into the spark plug well.

Push the rubber dust boot over the top of the new plug.

Line up the bolt hole in the ignition coil with the corresponding bolt hole in the intake manifold.

Tighten Clockwise
Line Up Power Plug
Push On Connector
Replace the black bolt and spin it in a few turns in the clockwise direction to prevent it from becoming cross threaded.

Tighten the ignition coil bolt in the clockwise direction with the 8mm wrench until it is snug.

Try to avoid over tightening the bolt to prevent from cracking the plastic ignition coil housing.

Slide the electrical connector straight on to the ignition coil assembly.

Slide In White Lock Tab
Ignition Coil Secured
Lower Plastic Cover
Slide the white plastic locking tab straight in towards the ignition coil to secure the connector in place.

Carefully lower the plastic cover down into the place over the top of the engine.

Replace Front Left Nut
Rear Right Nut
Front Right Bolt
Replace the two 10mm nuts and the two 8mm bolts.
Rear Left Bolt
Tighten Clockwise
Spark Plug Change Done
Double check that the four engine cover fasteners are secure.

Start the engine and listen closely for any strange sounds that might indicate a loose spark plug or a disconnected electrical connector.

If you do hear a weird noise, immediately turn off the ignition and double check your work.

Be sure to write down the spark plug change in your car's service records.

According to the scheduled maintenance section of the owner's manual the spark plugs should be replaced every 100,000 miles (or 160,000 km).

For more, please check out all of the 2015-2022 Ford Mustang DIY Repair & Maintenance Guides.

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