How to Replace Ignition Coils on a 2018 Dodge Challenger (Fix Misfires & Rough Idle)
Step-by-step coil-on-plug replacement with tools list, parts, safety tips, and 8 Nm (71 in-lb) torque spec for 2008, 2009, 2010
How to Replace Ignition Coils on a 2018 Dodge Challenger (Fix Misfires & Rough Idle)
Step-by-step coil-on-plug replacement with tools list, parts, safety tips, and 8 Nm (71 in-lb) torque spec for 2008, 2009, 2010
🔧 Challenger - Ignition Coil Replacement
Your Challenger uses coil-on-plug ignition coils (one coil per cylinder) mounted on top of the valve covers. Replacing a bad coil restores a strong spark and can fix misfires, rough idle, and flashing check-engine lights.
Difficulty Level: Beginner | Estimated Time: 1.0–2.0 hours
⚠️ Safety & Precautions
- ⚠️ Work on a cool engine; coils sit near hot parts.
- ⚠️ Disconnect the negative battery cable to prevent accidental shorts.
- ⚠️ Don’t pull on wiring; release connector locks first.
- ⚠️ If the check-engine light is flashing, avoid driving until fixed (can damage the catalytic converters).
🔧 Required Tools
You'll need the following tools for this repair:
- 10mm socket
- 1/4" ratchet
- 3" socket extension
- Torque wrench (inch-pound or low Nm)
- Small flathead screwdriver
- Trim removal tool
- Nitrile gloves
- Safety glasses
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Ignition coil - Qty: 1 (or Qty: 8 if replacing all)
- Dielectric grease - Qty: 1
📋 Before You Begin
- Park on level ground, put the transmission in 1st gear, and set the parking brake.
- Let the engine cool fully.
- Open the trunk and disconnect the battery: use a 10mm socket to remove the negative terminal (black). Tuck it aside so it can’t spring back.
- Tip: Replace one coil at a time.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Remove the engine cover (if equipped)
- Grasp the cover and pull upward to release the rubber grommets. Use a trim removal tool if it’s tight.
- Set the cover aside where it won’t get scratched.
Step 2: Locate the coil you’re replacing
- Each coil sits directly on top of a spark plug along the valve covers (4 per side).
- Identify the coil by cylinder location if you’re tracking a misfire code (example: P0302 = cylinder 2).
Step 3: Unplug the coil electrical connector
- Use a small flathead screwdriver to gently lift the connector’s lock tab (if present), then press the release and pull the connector straight back.
- Tip: Wiggle the connector—don’t yank the wires.
Step 4: Remove the coil retaining bolt
- Use a 10mm socket, 3" socket extension, and 1/4" ratchet to remove the coil mounting bolt.
- Keep the bolt safe; you’ll reuse it.
Step 5: Remove the ignition coil
- Pull the coil straight up while gently twisting.
- If it feels stuck, keep twisting and pulling upward—don’t pry hard on the valve cover.
Step 6: Prep and install the new coil
- Put a very small amount of dielectric grease inside the new coil boot. (Dielectric grease is a silicone grease that helps seal out moisture and makes future removal easier.)
- Push the coil straight down onto the spark plug until it fully seats.
Step 7: Reinstall and torque the coil bolt
- Start the bolt by hand to avoid cross-threading.
- Use a torque wrench and 10mm socket: Torque to 8 Nm (71 in-lb).
Step 8: Reconnect the electrical connector
- Push the connector on until it clicks/locks.
- Give it a gentle tug to confirm it’s latched.
Step 9: Repeat for any other coils (if replacing more than one)
- Repeat Steps 2–8 for each additional coil.
Step 10: Reinstall the engine cover and reconnect the battery
- Press the engine cover back onto its grommets.
- Reconnect the negative battery cable using a 10mm socket. Snug it firmly (do not overtighten).
✅ After Repair
- Start the engine and let it idle for 1–2 minutes. It should run smooth.
- Check for a check-engine light and listen for a steady idle.
- If you have a scan tool, clear stored misfire codes and confirm none return after a short test drive.
- If it still misfires, the issue may be the spark plug, injector, or wiring at that cylinder.
💰 DIY vs Shop Cost
Shop Cost: $180–$450 (parts + labor, depends on how many coils)
DIY Cost: $50–$480 (parts only, depending on 1 vs all 8)
You Save: $130–$250+ by doing it yourself!
Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.8–1.5 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.


















