I just had a throttle problem similar to yours. The spring that pulls the bottom throttle peice back isn't strong enough to pull it all the way. The peice I'm talking about is right below where your throttle cable comes in and hooks to the round plate. It then has a linkage that hooks to the lower plate and it's the one with the spring that's sticking or worn. Spray a little WD-40 on it and work it. Mine would kick down if I hit the throttle pedal quickly and let off. Hope this helps <img src="/forums/images/graemlins/confused.gif" alt="" />
Later,
Nick