Ignition Coil Replacement
Also called coil change
The ignition coil generates the high voltage that makes the spark plug fire. When a coil breaks down, usually under load or when hot, that cylinder misfires: the car shakes, loses power and the check engine light often flashes. We identify the affected cylinder from live data and confirm by testing or swapping the coil before replacing it. A new coil will not fix a misfire caused by a worn plug, a blocked injector or low compression on that cylinder.
Signs you need this
- Check engine light flashing while the engine shakes
- Rough idle and a noticeable loss of power
- Misfire that appears when the engine is hot or under load
- Jerking during acceleration
- A fault code naming a specific cylinder misfire
Not all of these have to be present, and one of them on its own can mean something else entirely. That is what the diagnosis is for.
What the job includes
- Misfire counters read to identify the affected cylinder
- Coil tested electrically, and swapped between cylinders to confirm the fault follows it
- Spark plug on that cylinder inspected and replaced where needed
- Coil boot, connector and wiring inspected for tracking and oil contamination
- Correct specification coil fitted and secured to torque
- Codes cleared and a road test with misfire counters monitored
How we do it
Find the cylinder
Live misfire counters identify which cylinder is failing and whether the misfire is constant or load related.
Swap to confirm
The suspect coil is swapped with a neighbouring cylinder; if the misfire moves with it, the coil is proven faulty.
Check the plug too
The plug on that cylinder is inspected, since a worn plug overloads a coil and is often the underlying cause.
Fit and seal
The correct coil is fitted with a sound boot and clean connector, and any oil leak into the plug well is noted.
Clear and road test
Codes are cleared and the car is driven under load with misfire counters watched to confirm the repair held.
How we work
The same on every job, which is why we can write it down.
Diagnosis before quote
We find the fault first. A price given over the phone for a noise nobody has heard is a guess.
The price is agreed first
You approve the work and the cost before a spanner is picked up. Extra work means another call.
Parts you can check
We tell you whether a part is genuine, OEM, aftermarket or used, and what each one costs.
Old parts returned
Ask and we will hand back whatever we replaced. It is the simplest proof that the job was done.
Book ignition coil replacement
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Tell us the car and the symptom
We will arrange a mechanic at your location, or a slot at the nearest workshop. No payment until the price is agreed.