Shuts off when driving at lower speeds

2000 MERCURY MARQUIS
4.6L • V8 • 2WD • AUTOMATIC
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CAMP.
  • MEMBER
  • 21 POSTS
Car runs great in gear. Drives great for about 2 minutes then at lower speed just shuts off, stops running..
May 1, 2021 at 10:17 AM
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JACOBANDNICKOLAS
  • Experienced Mechanic
  • 110,240 POSTS
When this happens, does the engine start right back up or does it have to sit for a few minutes and cool?

I'm asking because what you described sounds like it could be related to a failing crankshaft position sensor. When these sensors start to fail, oftentimes they are affected by heat.

Do me a favor. Take a look through this link and let me know if anything seems to mirror what you experience:

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

If it does seem to mirror what you experience and the engine doesn't start right away, here is what you need to do. When it refuses to start, check to see if the spark plugs are getting spark. Here is a link that shows how it's done:

https://www.2carpros.com/articles/how-to-test-an-ignition-system

If there is no spark, the first suspect is the sensor. Here is a link that shows in general how one is replaced:

https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

The attachments below are specific to your vehicle for replacement.

Please understand, at this point this is a theory, so let me know if you have questions and what you find.

Take care,

Joe

See pics below.
May 2, 2021 at 12:33 PM
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