That sounds more sour/jiggy than spooky. Mine does or did that same thing for awhile. He wasn't scared so to speak, but he wouldn't calm down and just walk on a trail ride.
My advice is essentially the same, except you can try putting him to work when he starts jigging and acting out. Try serpentines, direction and gait changes, figure 8s, side passing, etc. Anything to get his mind on you and remind him that if he doesn't want to behave he can work. That doesn't always work in my experience, but it does work for some horses. The ones it doesn't work on seem to just get better with a ton of calm riding.