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Mercury Grand Marquis Rough Idle

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

What are common reasons my Mercury Grand Marquis has a rough idle?

While there are a variety of reasons your Mercury Grand Marquis 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

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Related Mercury Grand Marquis Questions

See what others are asking about their Mercury Grand Marquis. Get answers from RepairPal's community of auto experts and enthusiasts.
Happens every day.stopped at traffic light,seems thst it wants to stall,but doesn't.driving about 40 45 mph it sort o...
So i have what i believe is refereed to as a “rough idle” on my 2003 grand marquis. while in my car at stop lights it...

Related Mercury Grand Marquis Problems

Find the most common driver-reported problems that are to blame when a Mercury Grand Marquis has a rough idle.
The throttle position sensor (tps) may fail. common symptoms of a defective tps can be rough idle, hard starting, he...
Bad spark plugs or an ignition coil can cause ignition misfire, which will illuminate the check engine light.
Mercury Grand Marquis Repairs and Prices
All costs based on RepairPal Fair Price Estimate™ averages. Actual prices may change depending on final diagnosis.

Mercury Grand Marquis 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