Injector Dynamic injectors require the use of the factory Honda lower injector cushion if you have a Honda B,D, F or H series. Honda had 3 different ones over the years, a thick soft one, a thin soft one and a thin hard one. The one that works best is the thick soft one, which came on most OBD1 cars, and now we have them in stock and ready to ship. If you had aftermarket injectors in the past and crammed them into the lower cushion, they may be stretched and no longer fit tight on these injectors, they should be replaced.