Misfire says fuel injector and intake manifold gaskets

Hello,

Can you tell me the exact code number that you are currently getting?
This can help determine the diagnostic process.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Thank you.

This issue could be due to low compression on that cylinder. Which can be due to bad piston rings, leaking valves etc.
So, checking the compression could be a good idea.

Here is a helpful guide on how to test the compression:

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

Also attached are the compression test procedure and chart below for your reference.

Please let me know what you find.
Thank you.

Hello,

The code P0301 and P0316 are both related to the misfire and the P0446 is related to EVAP canister vent valve, which is not likely the contributing factor to your issue.

I have replied to the original thread, that this issue can also be due to low engine compression. So, checking the compression is a good idea.

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

I have attached the codes and the related items that can trigger those codes below.

Please let me know of any questions.
Thank you.