Engine rattling noise

Hi and thanks for using 2carpros,com

The first thing I suggest is this. If the check engine light is staying on when the engine runs, you need to scan the computer for diagnostic trouble codes. Most parts stores will do it for free. Here is a quick video showing how it is done. Once you do this, let me know what codes are found.

https://youtu.be/YV3TRZwer8k

Many things can cause this issue, but based on your description, it sounds like the catalytic converter internal components may have come loose. If that happens, you will hear it rattle. Also, if it moves in a position that causes exhaust flow to be restricted, you will loose power. Take a look through these links.

https://www.2carpros.com/articles/bad-catalytic-converter-symptoms

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

https://www.2carpros.com/articles/catalytic-converter-replacement

Now, since you hear a rattle, what I want you to do is this. Take a rubber mallet and tap on the exhaust system to see if you can recreate the sound. If you can, have a helper determine where the noise is coming from.

If you can't recreate the noise, then follow the directions in the aforementioned link that discusses how to test one.

If you find the converter is bad, I attached a link that shows in general how one is replaced. Pictures 1 - 3 show location.

Let me know if this helps or if you have other questions.

Take care,
Joe