I have removed the throttle cable and it's not the pedal. I then removed the join between the two levers so they move independently to see which is stiff, the one that connects to the throttle cable moves freely and always returns to the close position. The other one, when push open remains open, I then have to give it a push before it releases, so I know it is that mechanism/spring. It doesn't appear to be catching on anything, which, is why I think I need to take it apart, but I'm a bit reluctant to do that since I'm not entire sure what is holding it all together.