Mercury Cougar Rough Idle

Learn if it's a simple fix or time to seek out a trusted technician.

What are common reasons my Mercury Cougar has a rough idle?

While there are a variety of reasons your Mercury Cougar has a rough idle, the most common 3 are a vacuum leak, an issue with the spark plugs, or a problem with the ignition coil.
of the time it's
Vacuum Leak
of the time it's
Spark Plugs
of the time it's
Ignition Coil

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Mercury Cougar Rough Idle Repair Symptoms

A failing ignition coil can create several symptoms: Check engine light comes on Engine runs poorly or stall Increased emissions Reduced fuel economy Car won’t start I...Read More
When spark plugs fail, the engine will struggle. The check engine light will come on, and it may appear either solid or flashing. The driver would likely notice one or more of t...Read More