Matt555

Don't use G siren, That has to do with ELS nor does it work for making people get out of the way. Do not press G at all, ELS + G = Siren selection. I just use the normal horn (H for me), If you hold G of course it's going to spazz out like that. Just plain in general don't use the G siren, It's a pain to work with and it doesn't make people get out of the way, Otherwise check your key bindings and see if anything is interfering with it, Or it could just be an ELS bug. What version of ELS are you using.
 
 
EDIT: Also, 
 
You don't HOLD G you just simply hit G to change the siren type, But personally i don't like or use it because people do NOT get out of the way when using it.