2000 Mustang GT 4.6 Clutch out

I need help or advice. I have the above vehicle, a 2000 Ford Mustang GT convertible 4.6 liter motor, 5 spd trans. Just turned 33,000 miles and my clutch acts like it is going out.

Now, I am not gonna tell you I haven't played with any, I have. But not that much. As you can see, with 33,000 miles and 6 years later, I've babied the car for the most part but can't understand why it would act like the clutch is going out. It is a non hydraulic clutch. I could not find an adjuster on either end of the cable. It's been taken care of up to this point by the dealer. Its starting to slip really bad at this point and just wondering if there was some adjustment someone else knows about or something else that could cause this effect. No, there are no warning lights on.

Thanks in advance,

G