I found the primary culprit when searching for "BMW Z3 Throttle Cable" it is called a "Rubber Grommet for Accelerator Pedal Linkage"(14) it costs $2.00 from this website. Also there is a Clip(11) that looks like it secures the grommet and the linkage to the gas Pedal as you can see in this diagram. However I cannot find the clip in a store online to replace it I will check with the Dealer to see if it is covered under the previous recall or if they can order the clip for me.
|Gas Pedal Linkage Diagram|
See Part 1 and Part 2 of this Blog Post