[Hozer 88GTConv]

The plastic pos everyone is talking about is called the clutch pawl. I had the exact problem 4 yrs ago.
The thing is, the self-adjusting mechanism is comprised of plastic teeth that wear out.
There is a simple test you can perform to verify the condition of your pawl. Basically, you crawl under your instrument cluster and take the load off of the cable by depressing the pedal all the way up. Then, you manipulate the pawl to it's highest position. You'll know it when you feel it. When you depress the pedal again, you should hear/feel the pawl adjust.
It is in your book I'm sure.
If you need it though, I can look it up.
Either way, get the aluminum kit, they give you a new cable too and you left calf will get strong.