'04 5-spd funky clutch problems... help!

I've posted this before but I will give it a shot again...

Since 15,000 miles, my '04 SXT 5-spd has had a wierd "sluggishness" between gear shifts. Basically, the clutch will SOMETIMES slip after hitting a gear and completely letting off the pedal... the amount of slippage can be a few thousand RPM's, and fall down to match the trans RPM after a few seconds. This has been a come-and-go problem for 5000 miles now.

I checked the fluid level in the master cylinder... topped off fine, just like the day I bought it, and it looked clean. Originally (like the day it first happened) I thought my clutch might be going (although odd for only 15k miles). But 5000 miles later, don't think so. It also seems temperature dependant. Below 32 degrees F, it happens much more and slips more during engagement of the clutch... above 32 degrees, it happens less, or sometimes not at all. Sometimes if it is happening, I can pump the master cylinder and get ***loads of grip with the clutch.

Any suggestions? Like I said, it comes and goes. Maybe one out of 3 or 4 days it will have this problem. I have heard of funky things happening to fluids and wierd problems that come from them, but I don't have too much bad experience with hydraulic clutch problems. Any suggestions?

Not sure if the same thing for you but I know on my SRT4 there have been weird problems especially when it's cold. Personally, I have not had this problem. Take it to the dealer. It could be a glazed flywheel which is a simple fix.