Check engine light on and code P0300

Hi,

A P0300 is a random misfire and isn't specific to any one cylinder. So, that simply means it could be the result of a few different things.

Since it is random and not specific, I doubt it is a spark plug or anything like that. What I would start with would be to simply check for engine vacuum leaks. Any unmetered air getting into the engine will cause issues.

Here is a link that shows how that is done:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

If nothing is found, the next thing I would check is fuel pressure. Fuel pressure that is too high or low can cause a misfire as well. Here is a link that shows how that is done:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

I attached the manufacturer's fuel pressure specifications below.

If you have a live data scan tool, let me know what the short-term fuel trims are as well as what the coolant temp sensor's signal is when the engine is cold and not started for the day.

Let me know what you find or if you have other questions.

Take care,

Joe

See pic below.