Car trouble · Engine & check-engine light

My check engine light is flashing

A blinking check-engine light means the engine is misfiring badly right now. Unburned fuel can overheat and destroy the catalytic converter.

Stop driving it

A flashing light means an active misfire that can damage the engine and catalytic converter within miles. Pull over, and get it towed or checked before driving further.

A starting point, not a diagnosis. Most parts stores read check-engine codes and test batteries for free.

Likely causes — tick the parts you want

A failed ignition coil
most likely · Doable with tools and a free afternoon
How to check: Have the code read — a misfire code names the cylinder. If the engine shakes at idle and runs rough, a coil on that cylinder is a common cause.
- Ignition coil(Ask the counter to read the check-engine code for free — most parts stores will.)
Worn or fouled spark plugs
possible · Doable with tools and a free afternoon
How to check: Check your records for when the plugs were last changed. Many are due somewhere between 60,000 and 100,000 miles — the owner’s manual says.
- Spark plugs (set)(Ask how many this engine takes and whether they come pre-gapped.)
- Spark plug socket
A fuel injector or internal engine problem
less likely · A mechanic’s job
How to check: If new plugs and a coil don’t clear the misfire on that cylinder, it needs a mechanic to test the injector and compression.

Your car — the counter needs this

YearMakeModelEngine (optional)

VIN (optional, most exact)Which parts store (optional)

If the counter doesn’t have a part, your shopper asks them to order it under your name and messages you the order number. When it comes in, send someone to collect it.

Not quite it?

My check engine light is on My oil light is on My engine idles rough or shakes My car hesitates when I accelerate I smell burning oil My car is getting worse gas mileage