I just spent the weekend basically porting and polishing a throttle body and halving the shaft for my for my AU and proceeded to test it today but it's sticking when I hold the throttle at a cruising speed, it will return after punching the throttle as it obviously snaps shut. I've removed it again and compared it to my standard throttle out of the car and it shuts in the same fashion, doesn't stick when cracked open and seams to be exactly the same when it opens and closes. The spring on the side of the body also seams to be just as strong on each throttle.

I was thinking of replacing the spring that pulls the throttle shut, the one that connects to the bracket on the base of the throttle body but I feel that this will just mask the issue.

Besides getting a 68mm throttle from Ebay does anybody have any ideas, um, help??

This is basically the processes I followed and where I got the idea:

fordmods-technical-documents-diy-f38/improving-your-6cyl-e-series-throttlebody-the-diy-way-t84040.html

Butterfly not in upside down? The edges of the butterfly are angle cut and will jam if reversed. Also a backstop screw if present can be threaded out to stop the bf closing too much assuming idle isn't too high.