Installed the uprated OVP with new part number. So far the car starts fine. Driving to doctor, cinema, and shopping, the car starts every time. I disassembled the OVP relay box and found some oxidization on the I/C board. I think the problem was I/C board. Beside saving money, I accomplished something which makes me feel very good myself. Special thank to Arthur Dalton. He knows these stuffs very well.