I have an 06 G35X Sedan, and I am barely able to steer the car. I need to use almost all of my arm strength to turn the steering wheel when the engine is ON. There are no strange noises, the reservoir is full, but there is a little seepage from the rack. What could be doing this?

 

Probably the lower steering shaft u-joint seizing up, spray it down thoroughly with some teflon lubricant spray (maybe white lithium grease?). I don't really recommend WD-40 because it attracts so much dirt but it would work if that's all you have.

You can see it from the engine bay but it's easier to spray it from under the car.

Just be aware this isn't exactly a FIX, it's more of a band-aid that you can use for up to a year but if the spray fixes the issue then you should definitely start planning to replace that u-joint.