I have been researching my issue and this is the closest I have found to what is happening.

http://www.carproblemzoo.com/nissan/...e-problems.php

Issue # 6

It's only the first half of the issue on the website.

#6 - Clutch Pedal/linkage problem of the 2004 Nissan Maxima

The car is a 2004 Nissan Maxima. Basic symptom has been if the car sits idling in traffic jam, or after a 3-4 stop and go local trips, I develop a lot of play in the clutch pedal. Normally, when I apply light pressure to the clutch pedal, I feel resistance immediately. When its acting up, I feel significantly less resistance in the pedal from the top, sometime almost half way through the pedal travel. If I continue driving it usually clears up on its own or if I park and leave it for 30+ minutes. Definitely seems heat related and does not appear in the winter. Despite the "slop" in the pedal, the clutch appears to be shifting ok and engages about mid pedal travel.

The only difference in mine is it doesn't have to be stop and go traffic.

I am starting to think it's related to temperature as well as I purchased the car in the winter. I am thinking about flushing the hydraulic lines and replacing with amsoil. I don't know if that will fix it. Does anyone have any ideas as to what could be causing this?

 

Hey same thing happened to me. Granted i have a 02 6speed though. Usually after alot of driving the pedal resistance got really soft. What you can do is check the clutch fluid in the master cylinder. See if its really dark color. Like you said you might as well change it.

Another thing is check the rubber clutch line. It could be worn out or leaking. I noticed on mine that the rubber line going to the slave cylinder on the transmission was coated with oil and it was really dirty n gunked up. Im guessing it was starting to form a slow leak.

So ya i actually replaced it with a stainless steel clutch line and bleed the system with brand new fluids. All was well after that. You could just buy a new oem rubber line but for me i went the easier route

hope that helps

 

So Friday night, my clutch pedal hit the floor and wouldn't come back up. (On the frickin highway). Luckily there wasnt a lot of traffic and I was able to coast off to the side. Shut off the car and started it in first to get to a safer spot and pulled over. The fluid was extremely dirty. Looked contaminated. Went back into the car and some pressure came back and I was able to get home. I took it to a shop in the AM and flushed the system with prestone brake fluid and then filled the system with amsoil. So far so good. I am going to keep an eye on it but it has been running fine since.

 

Happened to me too. Thought at first it was a slave cylinder so I went and replaced it but after it happened again within a few months I figured out it was the clutch master. Its located behind the strut tower, doesn't get a lot of airflow and I believe it contributes to the issue.. Especially seeing it only acted up in summer months. Essentially the seals for the pressure chamber fail and bleed past when you depress the pedal. There's no pressure to return it resulting in a stuck pedal. So replace the clutch master. I waited too long and starting it in first gear too many times blew my starter as well lol.