Misfiring and check engine light on

Hello, I'm Danny.

The first thing that needs to be done is to perform a code check to determine the check engine light codes that are stored in your vehicles computer that is causing this misfire issue. Here is a tutorial showing what is involved to check for these codes:

https://www.2carpros.com/articles/toyota-trouble-code-definitions-and-code-gathering-method-1990-1995

Places like AutoZone auto parts stores can check codes for free. After doing this test get back to us with the code information and we can then properly diagnose. Hope this helps and thanks for using 2CarPros.

Hello,

Due to Covid and family issues, I had to leave the car sit. Had a mechanic look at it today, and there were no codes to pull.

After i drive the car for a few miles, the check engine light flickers quickly and the car is misfiring and jerking. After a while, the car will no longer misfire and jerk, and the check engine light becomes a solid color.

The light will stay on until you turn the car off. When you turn the car on, there will be no check engine light and no codes. The mechanic told me that it could be a muffler problem or a catalytic converter problem. Is this a good assessment?

Thank you!

A clogged catalytic converter can lead to a misfire also can cause poor fuel economy.

Here is a guide on how to test the catalytic converters:

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

Keep in mind that the misfire can also be caused by weak spark plugs. As they can misfire under certain load as you are driving.
Unless you have already done it, it will be good idea to check the plugs and make sure they don't have carbon build up and the gap is set correctly.
Those plugs should be gapped at 0.031 inch.

https://www.2carpros.com/articles/how-to-change-spark-plugs

Also, engine can misfire due to worn components like distributor cap, rotor, wires etc.

Please let me know of any questions.
Thank you.