When the car is idling I can smell raw fuel coming out of the exhaust pipe and not only that, but my MPG has dropped.

Another thing I've noticed is that the car (feels like the engine...) quivers (slight tremble) every 2-3 seconds when the RPM is only around 1,800 or so. Never happens when its below or above that RPM.

Any one have suggestions?

are you leaking fuel?

I don't think you mentioned the year and engine size. But if it has multi-port fuel injection, you may have an injector not closing.

O2 sensor.

Thought I forgot something. :) It's an 89 w/1.9L CFI.

No I'm not leaking any fuel that I can tell from where the car is parked.

I checked the O2 sensor with a MM and when the car is idling the MM shows -0.2V. When I rev it up it increases(to a positive #). Though having it display -.2v looks wierd, I don't think thats normal... right?

sound's like you're running pig rich