How to Replace Ignition Coils on a 2021 Jeep Gladiator (Fix Misfire & Rough Idle)
Step-by-step coil swap with required tools/parts, OBD2 misfire checks, and 80 in-lb (9 Nm) torque spec for 2020, 2022
How to Replace Ignition Coils on a 2021 Jeep Gladiator (Fix Misfire & Rough Idle)
Step-by-step coil swap with required tools/parts, OBD2 misfire checks, and 80 in-lb (9 Nm) torque spec for 2020, 2022
đź”§ Gladiator - Ignition Coil Replacement
Your Gladiator’s ignition coils sit on top of the spark plugs and create the high voltage needed for ignition. Replacing a bad coil can fix a misfire, rough idle, flashing check-engine light, and loss of power.
Difficulty Level: Beginner | Estimated Time: 0.5-1.5 hours
⚠️ Safety & Precautions
- Work on a cold engine to avoid burns and to prevent damaging coil boots.
- Keep the key out of the vehicle while unplugging ignition connectors.
- If you disconnect the battery: use a 10mm wrench and remove the negative terminal first.
- Do not pull on wiring—release the connector lock and pull on the connector body.
đź”§ Required Tools
You'll need the following tools for this repair:
- Safety glasses
- Nitrile gloves
- 10mm socket
- 1/4" drive ratchet
- 1/4" drive extension set (3" and 6")
- Torque wrench (inch-pound)
- Trim clip/pick tool
- Flashlight
- OBD2 scan tool
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Ignition coil - Qty: 1 (or Qty: 6 if replacing all)
- Dielectric grease - Qty: 1
đź“‹ Before You Begin
- Park on level ground, shift to neutral, set the parking brake, and open the hood.
- Let the engine cool fully.
- If you have a misfire code, plug in your OBD2 scan tool (a small code reader for the diagnostic port) and note which cylinder is misfiring (example: P0302 = cylinder 2).
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Remove the engine cover (if equipped)
- Use your hands to pull straight up on the engine cover to release the grommets, then set it aside.
- Use a flashlight to locate the coils (one coil per cylinder on top of the valve covers).
Step 2: Unplug the ignition coil electrical connector
- Use a trim clip/pick tool to gently lift the connector lock (if present), then press the release tab.
- Pull the connector straight off the coil (do not pull on the wires).
Step 3: Remove the ignition coil retaining bolt
- Use a 10mm socket, 1/4" drive ratchet, and a 1/4" drive extension (3" or 6") to remove the coil bolt.
- Set the bolt somewhere safe so it doesn’t fall into the engine bay.
Step 4: Remove the ignition coil
- Grip the coil body and twist it slightly to break the seal, then pull straight up to remove it.
- If it feels stuck, keep twisting gently—don’t pry on the valve cover.
Step 5: Prep and install the new ignition coil
- Apply a very small dab of dielectric grease (silicone grease that helps prevent moisture and sticking) inside the new coil boot.
- Push the new coil straight down onto the spark plug until it fully seats.
Step 6: Reinstall and torque the coil bolt
- Start the bolt by hand to avoid cross-threading.
- Use a 10mm socket and torque wrench (inch-pound) to tighten the bolt: Torque to 9 Nm (80 in-lbs).
Step 7: Reconnect the electrical connector
- Push the connector on until it clicks/locks.
- Use a flashlight to double-check the connector is fully seated and the wiring isn’t pinched.
Step 8: Reinstall the engine cover
- Align the cover over its mounting points and press down firmly with your hands until it snaps into place.
- Push near grommets, not the center.
âś… After Repair
- Start the engine and let it idle for 1-2 minutes. It should run smooth with no shaking.
- Use your OBD2 scan tool to clear stored misfire codes, then recheck for returning codes.
- Road test for 10-15 minutes. If the check-engine light flashes again, stop driving and rescan (flashing = active misfire that can damage the catalytic converters).
đź’° DIY vs Shop Cost
Shop Cost: $180-$550 (parts + labor, depending on 1 coil vs all 6)
DIY Cost: $35-$330 (parts only)
You Save: $145-$220+ by doing it yourself!
Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.7-1.5 hours.
🎯 Ready to get started?
HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.


















