Okay i dont know whether it is opti related or fuel....

symptoms: problem when i try to start the car(takes awhile to start)
car sounds different (not as strong as before)
HORRIBLE GAS (like 8-9m.p.g)
performance loss(car always runs different but 9 out of 10 times its not good)

 

I would try fuel filter, ussually when the pump goes bad it will run good when you first start it. If it is the opposite maybe a bad o2 sensor.

 

I'd be checking for a stuck or leaking fuel injector or crapped out fuel pressure regulator. If you've got a hard start issue coupled with a drastic loss in gas mileage, that would be a couple of my first things on the list to check.