Diagnosis code P0300

Hello,

Okay, Direct Trouble Code[DTC] P0300 is just a a DTC for a random misfire. DTC's P0301-P0310 are DTC's for specific cylinders with the numbers after the 3 being the cylinder number. I would check for a vacuum leak, inspecting the air intake tract, throttle body, intake manifold, and all vacuum and EVAP hoses. Look for cracked, cut, or heated dry rotted hoses, make sure the intake air tract pieces are all securely fitted together, and that the throttle body and intake manifold gaskets are not leaking. If you are worried about your vehicle's cylinder head having a hairline crack in it, you can do a compression test on your vehicle and that will let you know if there is one. A hairline crack will let the compression bleed out on the cylinder where it is. If it is in between cylinders, then you will probably be leaking coolant out of it and it will be mixing with the engine oil and possibly causing a hydrolock symptom in the effected cylinder. Here is a link down below on how to do a compression test:

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

Here is one on testing for vacuum leaks:

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

Please go through these guides and get back to us with how everything turns out. We can go from there.

Thanks,
Alex
2CarPros

Hello again,

I have sent along some information that might be helpful to you on misfire DTC's in the diagrams down below. This guide is from the vehicle manufacturer and should help you as you go through the previous diagnostic troubleshooting guide by understanding why you are looking at the things the guide asks you to look at. I hope this helps ad please get back to us with what you find out.

Thanks,
Alex
2CarPros