Originally Posted by joejo

i was running my truck the other day, (mach .26) and my high speed needle was set about 2.125 turns out. its been this way for a long time and ran great. however just like someone threw a light switch it ran extremely rich almost to the point where it wouldn't run. at full throttle it wouldn't even move. this happend immediately. i ended up turning the hsn in a full turn to get it to run good again. now its only a little over 1 turn out. what could have happened? i pulled the needle to see if it broke off or something, but everything looks good.
any input? thanks