i was wondering what these plastic pieces are called and what problems would be caused if i left them out. they slide down in the bore for the primary injectors.
how often do people leave these out?

 

They are the primary injector diffusers. They are supposed to help with fuel atomization & improve idle.

 

I'm running all four (prim/sec) top feed injectors and have had them removed with no problems.

 

ok thanks guys thats what i was thinking that they were for. i guess ill give it a shot with out them and see how it idles

 

I didn't have them in the primarys for ten years and didn't notice anything--as long as the motor was warm. I would not leave them out of the secondary though, as atomization is more problematic here. You want to avoid washing the walls down with raw gas where possible.