Code P0300, flashing Check Engine Light?

CARLSP

MEMBER
2006 HYUNDAI AZERA
3.8L
V6
2WD
AUTOMATIC
180,000 MILES

Car starts fine but then idles and runs really rough, The CEL is flashing and the only code I get is P0300. My question is, where do I start looking to find the cause of this random misfire? The oil cap was loose and so all the oil sprayed out over the engine. Drained out the oil and replaced it along with new filter. The oil that came out of the car was really black, very thick, almost like molasses, and smelled bad.

Sunday, February 16th, 2025 AT 11:04 PM

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
51,500 POSTS

When the engine is running does it make irregular noises? I would do a compression test to see if the engine is having a mechanical issue or upload a short video of the engine running so I can see and be able to tell what's going on.

A P0300 code indicates a random/multiple cylinder misfire detected.

Here is a guide to help you understand engine misfires:

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

and

https://www.2carpros.com/articles/how-to-test-engine-compression

Once you go over these guides or send the video, we can make a game plan on how to proceed.

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Tuesday, February 18th, 2025 AT 10:15 AM