Broken high speed needle?
 

I think my high speed/idle needle may be broken. I've tried adjusting it, and fiddling with it for awhile, and it doesn't do anything.

Suggestions?

check the o rings they might be worn out & dismantle it look at the actual needle might be damaged good luck

Along with checking the O-Ring, it may also help to take the needle out and and with and exacto knife gently scrape the needle to get any build up off of the needle as well as create a clean mor precise surface. I have done this in the past and it has made a difference