Full Engine Tune-Up

Complete tune-up service for the 2008 Dodge Viper 8.4L V10, including spark plug replacement, ignition coil inspection, throttle body cleaning, and air filter replacement.

Warnings

Tools required

Parts

• Spark plugs (NGK or Champion copper core recommended) × 10 — Use OEM specification or equivalent
• Engine air filter × 1 — Mopar 4891927AA or equivalent

Preparation

1. Ensure engine is completely cold to the touch (minimum 2 hours after last operation).
2. Disconnect battery negative terminal and secure away from battery post.
3. Remove engine cover by releasing hold-down clips and lifting straight up.
4. Verify replacement spark plugs are gapped to 0.045 inches (1.14mm) specification.
5. Organize workspace with labeled containers for fasteners from left and right cylinder banks.

Procedure

1. 1

   Remove air intake system
   Disconnect the mass airflow sensor electrical connector by pressing the release tab and pulling straight out. Loosen the intake tube clamps at the throttle body and air filter housing. Remove the entire intake tube assembly from throttle body to air filter housing. Remove the air filter housing lid fasteners and lift the lid to access the air filter element.
2. 2

   Replace engine air filter
   Remove the old air filter element from the housing. Inspect the housing interior for debris, dirt, or moisture. Clean with compressed air if necessary. Install the new air filter element, ensuring it seats properly in the housing with no gaps around the perimeter. Reinstall the air filter housing lid and secure all fasteners.
3. 3

   Remove ignition coils from right cylinder bank (cylinders 2, 4, 6, 8, 10)
   Starting with the right side of the engine (passenger side), disconnect the electrical connector from each ignition coil by pressing the locking tab and pulling straight up. Remove the single 10mm bolt securing each coil pack. Carefully pull each coil straight up with a twisting motion to break the seal. Mark each coil with its cylinder number using tape or marker. Note: Remove ignition coils from one cylinder bank (verify cylinder-to-bank numbering against factory service manual before marking)
   ⚠Do not pull on coil wiring harness. Grasp the coil body only to prevent harness damage.
   Torque spec

   Ignition Coil Bolts8 Nm (6 lb-ft)
4. 4

   Remove ignition coils from left cylinder bank (cylinders 1, 3, 5, 7, 9)
   Repeat the coil removal process for the left side of the engine (driver side). Disconnect each electrical connector, remove the 10mm mounting bolt, and carefully extract each coil with a twisting motion. Mark each coil with its cylinder number. Note: Remove ignition coils from the opposite cylinder bank (verify cylinder-to-bank numbering against factory service manual before marking)
   Torque spec

   Ignition Coil Bolts8 Nm (6 lb-ft)
5. 5

   Inspect ignition coils and boots
   Examine each ignition coil boot for cracks, carbon tracking, or oil contamination. Check the coil spring contact inside each boot for corrosion or damage. Replace any coils showing signs of damage or degradation. Clean minor dirt buildup with a lint-free cloth.
6. 6

   Remove spark plugs from right cylinder bank
   Use compressed air to blow out any debris from around each spark plug well before removal. Using the correct spark plug socket size for the specified plugs (verify 5/8" vs 9/16" against the plug application) and an extension, carefully remove all 5 spark plugs from this cylinder bank. Keep plugs organized in order to allow for wear pattern inspection.
   ⚠Ensure spark plug socket rubber insert is in good condition to prevent dropping plugs into engine bay during removal.
7. 7

   Remove spark plugs from left cylinder bank
   Repeat the spark plug removal process for the left cylinder bank. Use compressed air in each plug well before removal, then extract all 5 spark plugs using the spark plug socket. Keep plugs organized by cylinder for inspection.
   Torque spec

   Spark Plugs — Aluminum Head20 Nm (15 lb-ft)
8. 8

   Inspect old spark plugs
   Examine each spark plug for wear patterns, electrode erosion, oil fouling, or abnormal deposits. Normal plugs will show light tan to gray deposits. Heavy carbon, oil wetness, or white blistering indicates potential engine issues requiring further diagnosis. Note any cylinders showing abnormal conditions.
9. 9

   Install new spark plugs
   Do not apply anti-seize to plated spark plug threads unless the plug manufacturer specifies it. Hand-thread each spark plug into its cylinder to prevent cross-threading. Once all 10 plugs are hand-tight, use the torque wrench and spark plug socket to tighten each plug to the factory-specified torque value (verify against the 2008 Viper 8.4L service manual before tightening).
   ⚠️Critical: Aluminum cylinder heads are easily damaged by over-torquing. Use a calibrated torque wrench and do not exceed 15 lb-ft.
   Torque spec

   Spark Plugs — Aluminum Head20 Nm (15 lb-ft)
10. 10

    Reinstall ignition coils
    Apply a thin coat of dielectric grease to the inside of each coil boot. Install each coil back into its marked cylinder position, pressing down firmly until fully seated. Install the mounting bolt for each coil and torque to the factory-specified value (verify against the 2008 Viper 8.4L service manual). Reconnect each coil electrical connector, ensuring the locking tab clicks into place.
    Torque spec

    Ignition Coil Bolts8 Nm (6 lb-ft)
11. 11

    Clean throttle body
    With the intake tube still removed, inspect the throttle body bore and throttle plate for carbon deposits. Spray throttle body cleaner onto a clean shop towel and wipe the throttle bore and plate surfaces. Do not spray cleaner directly onto the throttle position sensor or electronic actuator. Allow any residual cleaner to evaporate before reassembly.
    ⚠Do not force the throttle plate open manually. The electronic throttle control system can be damaged by forced movement.
12. 12

    Reinstall air intake system
    Position the intake tube assembly between the throttle body and air filter housing. Secure both clamps, ensuring proper seating before tightening. Reconnect the mass airflow sensor electrical connector until it clicks. Install the engine cover by aligning the mounting points and pressing down until all clips engage.
13. 13

    Reconnect battery and perform idle relearn
    Reconnect the battery negative terminal and tighten securely. Start the engine and allow it to idle for 2-3 minutes without touching the accelerator pedal. The PCM will relearn idle parameters and throttle position. Monitor for smooth idle and check for any unusual noises or misfires.

Reassembly

1. Reinstallation follows removal in reverse order.
2. Ensure all ignition coil electrical connectors are fully seated and locked.
3. Verify engine cover clips are fully engaged before operating vehicle.
4. Double-check all intake system clamps are tight to prevent vacuum leaks.

Verification

• Start engine and verify smooth idle with no misfires or rough running.
• Check for proper engagement of all ignition coil connectors (no illuminated check engine light).
• Confirm no vacuum leaks at intake connections by listening for hissing sounds.
• Test drive vehicle through various RPM ranges to verify smooth acceleration and no hesitation.
• If equipped with a scan tool, verify all cylinders show proper firing and no misfire codes are present.

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

Chasing one of these codes and not sure which part is guilty? Ask a master mechanic about YOUR car →

More procedures for this vehicle