What kind of ecu do you have now? If its a pm6 from a 88-91 si it will work but performance will suffer a little bit, which might be what your describing. Most people opt for the integra ecu (PG7) because it gives you the better fuel curves, some people say it idles a little funny but otherwise works great. Or you could always get the ZC ecu (PM7) its hard to find but its made for the engine.