I have been dealing with Engine Misfire codes (P0300 to P0304) on my 2003 Toyota MR2 Spyder. I changed the spark plugs and engine coils. That did not clear the codes. I used OBD scanner to erase the codes but every time I did, P0300 to P0304 kept coming back instantly and check engine light also came back instantaneously.
So I decided to go old school and unplug the battery and let the car sit overnight. I turned the car on this morning and no codes showed up and check engine light did not come up either. I Kept it running for 10-15 minutes and still no codes showed up and no check engine light came up.
I am not sure if the problem is fixed or not as I do not know if the previous attempts of erasing the codes did not erase the codes or do I need to keep the car running for a little longer for the codes to appear again.
Any help is highly appreciated.