MPV 2004 Engine Light On-OFF
 

Hi, My MPV check engine light comes on after filling Gas or while driving. Checked-tighten gas cap some time resolves the issue but comes on again while driving.
Sometimes while driving, got mild jurks and engine light start flashing and after some time it stays on for 2-5 days, but my car runs normal.

Mechanic checkes but found nothing, he is suspecting distributor or oxegen sensor.

Can any expert help me to reslove this issue?
Thanks in advance.
Sik.