SOLVED: Engine Misfire at Idle – Found the Fix
Quote from CarGuyBrad on June 11, 2025, 1:05 pm🚩 Symptoms:
Rough idle, shaky engine at stop lights.
Slight loss of power.
CEL ON with code P0302 (Cylinder 2 Misfire).
🔍 My Troubleshooting:
1️⃣ Swapped spark plugs — no change.
2️⃣ Swapped ignition coils — misfire moved to cylinder 4 → faulty ignition coil confirmed.🔧 My Solution:
Replaced all ignition coils & spark plugs together.
Cleared codes, car idles smooth now.
📌 Root Cause:
Failing ignition coil causing cylinder-specific misfire.
🔧 Problem Status: Fully Solved ✅
🚩 Symptoms:
-
Rough idle, shaky engine at stop lights.
-
Slight loss of power.
-
CEL ON with code P0302 (Cylinder 2 Misfire).
🔍 My Troubleshooting:
1️⃣ Swapped spark plugs — no change.
2️⃣ Swapped ignition coils — misfire moved to cylinder 4 → faulty ignition coil confirmed.
🔧 My Solution:
-
Replaced all ignition coils & spark plugs together.
-
Cleared codes, car idles smooth now.
📌 Root Cause:
Failing ignition coil causing cylinder-specific misfire.
🔧 Problem Status: Fully Solved ✅
Quote from CodeHunterJoe on June 16, 2025, 12:12 pmGreat way to isolate the faulty coil! Swapping coils cylinder-to-cylinder is my favorite simple method for misfire diagnostics. Easy and effective.
Great way to isolate the faulty coil! Swapping coils cylinder-to-cylinder is my favorite simple method for misfire diagnostics. Easy and effective.
Quote from DIYDan on June 18, 2025, 11:05 amIn my case, the misfire at idle was caused by a dirty throttle body. After cleaning it, the issue was completely resolved. Definitely worth checking!
In my case, the misfire at idle was caused by a dirty throttle body. After cleaning it, the issue was completely resolved. Definitely worth checking!
Quote from CheckEngineChamp on June 19, 2025, 11:07 amEngine misfire at idle can often be caused by a dirty throttle body or a vacuum leak. Cleaning the throttle body and checking for any cracked hoses usually solves the issue. Worked for me!”
If you want, I can give you 2-3 more variations so you can use them in replies — just tell me!
Engine misfire at idle can often be caused by a dirty throttle body or a vacuum leak. Cleaning the throttle body and checking for any cracked hoses usually solves the issue. Worked for me!”
If you want, I can give you 2-3 more variations so you can use them in replies — just tell me!
Quote from AutoFixerMike on June 19, 2025, 11:14 amIf your engine is misfiring at idle, the most common cause is often a faulty spark plug or coil. In my case, replacing a worn spark plug fixed the issue. Always start by checking plugs, coils, and vacuum leaks first — these are quick and inexpensive to inspect.
If your engine is misfiring at idle, the most common cause is often a faulty spark plug or coil. In my case, replacing a worn spark plug fixed the issue. Always start by checking plugs, coils, and vacuum leaks first — these are quick and inexpensive to inspect.