First, let me apologize for the essay but there are two posts in one.
Original post from other forum, no solution found. Thought i'd try my luck here.
"Hi Everyone,
For reference I have a mostly stock (for now) 2008 G37S Coupe. Any help would be much appreciated!

I have been noticing a variation in the pressure of the clutch pedal and its engagement point. The problem is that it occurs on random occasions but always when I first start the car in the morning. For example, this morning I started the car and noticed the clutch pedal had no resistance until very near the floor and when shifting gears it engages immediately. The first 3/4 of pedal travel has no pressure; i can push it down using one finger. Once I drive the car for a bit (5 to 10 minutes) the symptoms disappear and the car drives perfect however for the first bit it is difficult to drive because the clutch engages so suddenly. This is the first time in two weeks that this happened and there is no pattern to when it occurs.. seems like the car has occasional "bad days".

I took it to the dealership and left it overnight with them. They were unable to "duplicate the problem" and therefore nothing was done. I am now out of warranty and not sure what to do. It is really annoying having to deal with something that is problematic and takes away from the enjoyment of the car. The inconsistency makes it difficult to diagnose and has left me puzzled.

Does anyone have any insight on what the issue could be?? Thank you in advance for your help!!"

This member ended up taking it to the dealership to get the fluid flushed. They called him back hours later explaining how the fluid is not draining and they think the bleeder plug is clogged, there was no solution and he stopped posting after this update.

I have been having the exact same issue with my 2008 G37s. Started my car up last night and clutch would engage very low to the floor and have barely any pressure after engaging.

This morning i looked at the clutch fluid and it seemed very dirty so i went along and tried to flush it out. The fluid would not flush at all, i ended up taking a syringe to it and finally noticed clean clutch fluid flowing through, but there was still a lot of air bubbles. I kept trying but it didn't seem to get any better (i could not get rid of the air bubbles).

I pretty much gave up and just let my car idle for 15 min. At first the pedal was stuck to the floor with no pressure, came back 10 min later and the original symptoms were back (engaged very close to the floor with little pressure afterwards) 5 minutes later the pressure in the pedal seemed to go back to normal and the car drove fine.

Any suggestions or solutions? I feel like I have a bunch of air in the line that i couldn't get rid of although the clutch feels fine right now.