Out of nowhere a day ago, our honda odyssey vtec 3.5l van started vibrating as though its missing every couple of seconds. We checked the coil and replaced one of the cylinders seeming it was that. It worked fine for about 1/2 hour of driving and started again. Put the computer on the van and got p0300, 01, 02, etc (5 out of 6 cylinder misfires aswell as multiple random cyl. Misfires). Aswell as p1399 and p1457. Checked the plugs and it wasnt that. We are in the process of replacing flex and oxygen sensor. Could that be the problem or is there other suggestions? Oh, and the check engine light is on and blinking.