Engine
What are Spark Plugs?
Tiny igniters that set fire to the fuel inside your engine.
Simplified animation — not to scale.
In plain English
Spark plugs sit at the top of each engine cylinder (petrol engines only). They produce a precisely-timed spark that ignites the fuel-and-air mixture, pushing the piston down.
A simple analogy
"Like the clicker on a gas hob — a tiny zap that lights a much bigger flame."
How it works
High-voltage electricity jumps across a small gap at the tip of the plug, creating a spark thousands of times per minute as you drive.
Signs of trouble
- ⚠Engine misfires or judders
- ⚠Hard to start, especially when cold
- ⚠Worse fuel economy
- ⚠Engine management light
Rough UK cost
£60 – £180 for a set fitted
Always get a written quote. Prices vary by car, region, and parts brand.
Heads up: Carautonomy is for general guidance only. If your car is showing warning lights or behaving oddly, get it looked at by a qualified mechanic.