i had this problem too...check your coil wire for holes in the boot because it may be grounding out on your water pump.

 

Replaced the wire. Ordered a new harness, although last time I swapped out the opti the harness was fine. I decided not taking any chances this time.

 

when i swapped my opti, my harness looked fine too, as a matter of facrt i still have the old one and it still VISIUALLY looks fine lol, if i didnt already know there were a fault in it, id say it was fine....all i can say is looks can be decieving, they were to me i hope this fixes your problem bro, let us know how things turn out.