Close

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.
34%
of the time it's
Vacuum Leak
21%
of the time it's
Spark Plugs
15%
of the time it's
Ignition Coil

Get your Mercury issue diagnosed by a professional

Find a high quality auto repair shop or dealer near you
x

Related Mercury Cougar Questions

See what others are asking about their Mercury Cougar. Get answers from RepairPal's community of auto experts and enthusiasts.
rought idle or possible stall during hot weather. is this vapor lock?
Ignition went out so I replaced the ignition switch. Drove a couple days and car would not start. Somehow, the wires ...

Mercury Cougar Rough Idle Repair Symptoms

A failing ignition coil will create misfires in the engine, and lead to hesitation, extreme power loss, engine stalling, poor fuel mileage, and illumination of the check engine ...Read More
As we discussed, spark plugs are necessary for any gasoline engine to run. When they fail, the engine is in a constant state of attempting to ignite air and fuel, but cannot. Th...Read More