check engine light flashing

2001 JEEP CHEROKEE
190 MILES • 4.0L • 6 CYL • 4WD • AUTOMATIC
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PGARCIA99
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I recently had an oil change done at Les Schwab along with 4 new tires installed. When I started it up to leave it sounded louder than before. As I started driving my check engine light started to flash (it was on prior to that due to electrical issues it does not go off.) It almost died as I got in the highway I stopped at an AutoZone all 6 cylinders are misfiring. What could cause this? Les Schwab said they could do nothing for me. Haven't driven it since.
Jul 3, 2020 at 7:28 PM
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JACOBANDNICKOLAS
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Hi,

First, what was the light on for prior? Next, for them all to misfire, that leads me to think of something such as a crankshaft position sensor. Did it ever do this prior to having the work done?

I attached a pic of the sensor I mentioned. This sensor is responsible for fuel injection timing, ignition timing and can cause several issues. Check to make sure the connector to it wasn't damaged.

Also, let me know if there were any other codes found.

Take care,
Joe
Jul 3, 2020 at 10:18 PM
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PGARCIA99
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The check engine light was on before due to my oil sensor not working, even after an oil change it shows low oil. I haven't had any work prior to this being done but a normal tuneup about 2 years ago.
Jul 4, 2020 at 10:08 AM
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JACOBANDNICKOLAS
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It's odd that this happened after tires and an oil change. There are many things that can cause a misfire, but to have all cylinders doing it is odd unless it is a sensor issue. I mentioned the crankshaft position sensor above. There is also a camshaft position sensor that can cause such issues. I attached two pics below to help you locate it. Again, make sure the connection to it is tight.

Two things. First, you said it sounds louder than it did when you took the vehicle for service. Is it possible for you to record it running so I can hear it? Also, can you provide me with the diagnostic trouble codes that AZ gave you?

Let me know.
Joe
Jul 4, 2020 at 9:46 PM