How to Replace Ignition Coils on a 2018 Kia Forte (Fix Misfires & Rough Idle)
Step-by-step coil-on-plug replacement with tools, parts list, safety tips, and 7.2 ft-lb torque spec for 2014, 2015, 2016, 2017, 2018
How to Replace Ignition Coils on a 2018 Kia Forte (Fix Misfires & Rough Idle)
Step-by-step coil-on-plug replacement with tools, parts list, safety tips, and 7.2 ft-lb torque spec for 2014, 2015, 2016, 2017, 2018
🔧 Forte - Ignition Coil Replacement
Your Forte uses coil-on-plug ignition coils (one coil per spark plug). Replacing a weak coil can fix misfires, rough running, and a flashing check-engine light.
Difficulty Level: Beginner | Estimated Time: 0.5-1.0 hours
⚠️ Safety & Precautions
- ⚠️ Let the engine cool fully before starting (hot exhaust/valve cover burns).
- ⚠️ Turn ignition OFF and keep the key/fob away from the car while unplugging coils.
- ⚠️ If you disconnect the battery, you may reset radio presets and clock.
- ⚠️ Don’t pull on the wiring—only on the connector body and the coil.
🔧 Required Tools
You'll need the following tools for this repair:
- 10mm socket
- 1/4" drive ratchet
- 6" extension (1/4" drive)
- Torque wrench (in-lb or small ft-lb range)
- Small flathead screwdriver
- Nitrile gloves
- Safety glasses
- Shop towels
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Ignition coil - Qty: 1 (or Qty: 4 if replacing all)
- Dielectric grease - Qty: 1 (small packet/tube)
📋 Before You Begin
- 🧰 Park on level ground, shift to Park, and set the parking brake.
- 🧰 Open the hood and let the engine cool completely.
- 🧰 Optional but recommended: disconnect the negative battery terminal using a 10mm socket.
- 🧰 Decide your approach: replace only the failed coil, or replace all coils if mileage is high and you want even wear.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Remove the engine cover (if equipped)
- 🛠️ Lift up on the plastic engine cover to pop it off its mounting grommets (use your hands).
- 🛠️ Set it aside where it won’t get stepped on.
Step 2: Locate the ignition coils
- 🛠️ Look on top of the valve cover for the row of coil packs (one per cylinder) with electrical connectors.
- 🛠️ If you’re only replacing one coil, identify the correct cylinder first (misfire codes usually point to a cylinder).
Step 3: Unplug the coil electrical connector
- 🛠️ Press the connector lock tab and pull the connector straight off.
- 🛠️ If it’s stuck, use a small flathead screwdriver gently on the lock tab—don’t pry on wires.
Step 4: Remove the coil hold-down bolt
- 🛠️ Use a 10mm socket, 1/4" ratchet, and 6" extension to remove the coil bolt.
- 🛠️ Keep the bolt somewhere safe so it doesn’t fall into the engine bay.
Step 5: Remove the ignition coil
- 🛠️ Grab the coil body and twist slightly left-right while pulling upward to release the rubber boot from the spark plug.
- 🛠️ Inspect for oil inside the spark plug tube (oil can cause misfires and may indicate a valve cover gasket leak).
Step 6: Install the new coil
- 🛠️ Apply a tiny dab of dielectric grease inside the end of the coil boot (it helps prevent moisture and makes future removal easier).
- 🛠️ Push the coil straight down until it fully seats on the spark plug.
- 🛠️ Reinstall the hold-down bolt by hand first to avoid cross-threading.
- 🛠️ Tighten the bolt with a torque wrench: Torque to 9.8 Nm (7.2 ft-lbs).
Step 7: Reconnect the electrical connector and reassemble
- 🛠️ Push the connector on until it clicks and locks.
- 🛠️ Reinstall the engine cover by pressing it down onto the grommets (hands only).
- 🛠️ If you disconnected the battery, reconnect the negative terminal using a 10mm socket.
✅ After Repair
- ✅ Start the engine and listen for a smooth idle (no shaking).
- ✅ If the check-engine light was on, it may take a few drive cycles to clear; a scan tool can clear it immediately.
- ✅ Road test for 10–15 minutes and confirm no hesitation under light acceleration.
- ✅ If the misfire returns, the next common checks are spark plugs and oil in the plug tubes.
💰 DIY vs Shop Cost
Shop Cost: $180-$450 (parts + labor, depending on how many coils)
DIY Cost: $35-$280 (parts only)
You Save: $145-$170+ by doing it yourself!
Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.5-1.0 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.


















