Sometimes it can be helpful to try a new examination of conscience to ‘poke’ your conscience.
A different series of meditations or inquiries may yield new insights into unconfessed sins.
This is an examination that follows the commandments and the precepts of the Church.
I love this examination from Father Miller, CSsR, which offers a different focus for each month of the year.
This examination was put together by a SSPX priest friend of mine that is very helpful. (This will open a PDF for download).