25/02/2026
🚗 Engine not feeling quite right? Your spark plugs might be the reason.
Small part. Big impact. Worn spark plugs can reduce power, increase fuel consumption, and even lead to costly engine damage if left too long, whether you drive a modern daily or a cherished classic.
Here are 6 warning signs your spark plugs need replacing:
1️⃣ Rough or shaky idling
If your engine vibrates while stationary, inconsistent ignition could be the cause.
2️⃣ Slow or difficult starting
If your car struggles to fire up — especially on cold mornings — spark plugs may not be delivering proper ignition.
3️⃣ Engine misfires while driving
Jerking, hesitation, or uneven power delivery often points to faulty spark plugs.
4️⃣ Surging or loss of smooth acceleration
Unpredictable performance usually means inconsistent combustion.
5️⃣ Increased fuel consumption
Worn spark plugs make your engine work harder and burn more fuel.
6️⃣ Sluggish performance
If your car feels less responsive than usual, restoring proper spark can bring back lost power.
If you’re noticing any of these symptoms, our technicians can quickly diagnose the issue using advanced diagnostics and precision tools — protecting performance and preventing bigger repairs down the line.
We look after modern vehicles, classics, and fleet cars with the same attention to detail you expect from a specialist workshop.
Book your vehicle check today
📞Call 029 2000 2844
📧 Email [email protected]
Visit www.josephsullivan.co.uk
Based in Bedwas, Caerphilly
