Particle Objects do not follow close to path

Hi there. I am working on an animation that shows the directional flow of water along pipes. I have made a path that goes over the pipes and the arrows fly over the pipes. For the most part it works but what drives me crazy is that the arrows change distance from the path and seem to dance around.
I am using a path right next to the emitter and for the emitter, I am using a cone and emitting from the vertex. I have the clumping amount and shape to the lowest possible setting.
Here are some shots of the results and settings.

PIF2.blend (3.97 MB)
I’ve attached the blend file along with some screen shots.
Any help is much appreciated.

I think you need to change all your emitters to be single planes (one face) with the normals pointing in the direction you want the arrows to go. Then set the ‘Emit from’ to Faces instead of verts.

I forgot to say, you should also set the origin of your emitters and arrows to Geometry.