This light I speak of is Multi-Poin Fuel Injection.... I just finish my MPFI swap on my 89 civic DX, it started first try and it threw a code, and I started to get panicy, but then it was code 5, so i went and looked at my vaccum diagram again saw i had mixed my map sensor hoses up on the throtlebody and that fixed it. I timed the car and everything, then took it out for a spin... Holy shit it was like having a new motor!!!!! The car hauls now, and even with the DX cam at wide open throtle it make a sweet noise espcially at 4000+ RPM. I am about to go meet up with a buddy who has a ZC in his 4G hatch and see how it compares... To all you 4th gen DX or STD owners, I highly recommed this mod... I thought it was going to give me the same power gain as adding an intake i was way wrong.