Tune-Up - Minor

A minor tune-up for the 3.5L EcoBoost V6 including spark plug replacement, air filter replacement, and basic engine inspection to maintain performance and fuel economy.

Warnings

Tools required

Parts

• Spark plugs (6 required) × 6 — Motorcraft SP-546 or equivalent iridium
• Engine air filter × 1 — Motorcraft FA-1927 or equivalent
• Cabin air filter × 1 — Motorcraft FP-67 or equivalent

Preparation

1. Ensure engine is completely cold to the touch
2. Park vehicle on level surface and engage parking brake
3. Open hood and secure with prop rod
4. Disconnect negative battery terminal to prevent accidental electrical issues
5. Locate all six ignition coils on top of the engine (three per cylinder bank)
6. Have a clean workspace to organize ignition coils and hardware

Procedure

1. 1

   Remove engine cover
   Grasp the plastic engine cover firmly and pull upward to disengage the rubber grommets from the mounting posts. The cover is held by friction and does not have bolts. Set aside in a clean area.
2. 2

   Access and remove air intake system components
   Loosen the clamp on the air intake tube at the throttle body. Disconnect the mass airflow (MAF) sensor electrical connector by pressing the release tab. Release the air box clips and remove the upper air box housing to access the air filter.
   Torque spec

   Air Box Clips5 Nm (4 lb-ft)
3. 3

   Replace engine air filter
   Remove the old engine air filter from the air box. Inspect the air box housing for debris and clean if necessary using compressed air or a vacuum. Install the new air filter, ensuring it seats properly in the housing. Reinstall the upper air box housing and secure all clips. Reconnect the MAF sensor connector and air intake tube, tightening the clamp securely.
   Torque spec

   Air Box Clips5 Nm (4 lb-ft)
4. 4

   Replace cabin air filter
   Open the passenger door and locate the cabin air filter access door behind the glove box or under the dashboard (location varies by trim). Remove the access panel by pressing the release tabs. Slide out the old cabin air filter, noting the airflow direction arrow. Install the new cabin air filter with the arrow pointing in the correct airflow direction. Reinstall the access panel.
5. 5

   Remove ignition coils - Driver side bank
   Starting with cylinders 1, 2, and 3 (driver side bank), disconnect the electrical connector from each ignition coil by pressing the release tab and pulling straight up. Remove the single bolt securing each coil using the appropriate socket. Gently wiggle and pull each coil straight up to remove from the spark plug well. If resistance is felt, do not force - twist slightly while pulling. Mark or organize coils by cylinder position.
   ⚠Ignition coils can stick in the wells. Apply gentle twisting motion while pulling to avoid breaking the boot seal.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
6. 6

   Remove and inspect spark plugs - Driver side bank
   Use compressed air to blow out any debris from around each spark plug well before removal. Using the spark plug socket with extension, carefully remove each spark plug by turning counterclockwise. Inspect each old plug for abnormal wear, fouling, or incorrect gap. Check plug condition for signs of engine issues (oil fouling, carbon buildup, electrode erosion).
7. 7

   Install new spark plugs - Driver side bank
   Verify new spark plugs are gapped to manufacturer specification (typically 0.030-0.032 inches for EcoBoost, verify on plug box). Apply a small amount of anti-seize compound to the threads if plugs are not pre-treated. Hand-thread each new spark plug into the cylinder head to prevent cross-threading. Once hand-tight, use the torque wrench to tighten to specification. Apply dielectric grease to the inside of each ignition coil boot.
   ⚠Always hand-start spark plugs to avoid cross-threading. Cross-threaded plugs can cause catastrophic engine damage.
8. 8

   Reinstall ignition coils - Driver side bank
   Press each ignition coil firmly into its spark plug well, ensuring it seats fully on the spark plug. Install the mounting bolt for each coil and torque to specification. Reconnect the electrical connector to each coil, ensuring it clicks into place.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
9. 9

   Remove ignition coils - Passenger side bank
   Repeat the ignition coil removal process for cylinders 4, 5, and 6 (passenger side bank). Disconnect electrical connectors, remove mounting bolts, and carefully extract each coil. This side may have additional components in the way requiring careful maneuvering.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
10. 10

    Remove and inspect spark plugs - Passenger side bank
    Clean spark plug wells with compressed air. Remove each spark plug using the spark plug socket. Inspect plugs for wear and compare condition to the driver side plugs to identify any cylinder-specific issues.
11. 11

    Install new spark plugs - Passenger side bank
    Verify gap on new spark plugs. Apply anti-seize if needed. Hand-thread each spark plug, then torque to specification. Apply dielectric grease to ignition coil boots.
12. 12

    Reinstall ignition coils - Passenger side bank
    Install each ignition coil by pressing firmly into the spark plug well. Torque mounting bolts to specification and reconnect all electrical connectors.
    Torque spec

    Mounting Bolts31 Nm (23 lb-ft)
13. 13

    Perform final inspection and reinstall engine cover
    Verify all electrical connectors are secured and all mounting bolts are tightened. Check that no tools or parts were left in the engine bay. Reconnect the negative battery terminal. Align the engine cover with the mounting posts and press down firmly until all grommets seat properly.

Reassembly

1. Ensure all ignition coil electrical connectors are fully seated and locked
2. Verify air intake system is properly sealed with no loose clamps or disconnected hoses
3. Double-check that no tools, rags, or parts remain in the engine bay
4. Ensure engine cover is fully seated on all mounting posts

Verification

• Start the engine and verify it runs smoothly without misfires or rough idle
• Check for any diagnostic trouble codes using an OBD-II scanner
• Listen for any unusual noises or vacuum leaks around the intake system
• Allow engine to reach operating temperature and verify smooth acceleration
• Test drive the vehicle to confirm improved throttle response and no hesitation
• Verify no warning lights illuminate on the dashboard

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