Check engine light flashing

PGARCIA99

MEMBER
2001 JEEP CHEROKEE
4.0L
6 CYL
4WD
AUTOMATIC
190 MILES

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.

Friday, July 3rd, 2020 AT 7:28 PM

3 Replies

JACOBANDNICKOLAS

MECHANIC
110,055 POSTS

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

Image (Click to make bigger)

Was this

answer

helpful?

Yes

No

Friday, July 3rd, 2020 AT 10:18 PM

PGARCIA99

MEMBER
2 POSTS

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.

Was this

answer

helpful?

Yes

No

Saturday, July 4th, 2020 AT 10:08 AM

JACOBANDNICKOLAS

MECHANIC
110,055 POSTS

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

Images (Click to make bigger)