Ok, start I just swaped in a 99 D16y8 into a 93 hatch cx... Now I have a question and a problem for you tech's out there. Ok when I first swaped the Y8 in I was running the stock D15 ECU which is a p05 and it ran good and idled perfect. Of course I know I needed a p28 ECU to have VTEC to I got one. I wired the VTEC in did the 1 wire to 4 wire o2 conversion, but the engine revs up and down.... till it gets warm and idles fine. After this I drove it and VTEC engaged well and temperature is good and fan is coming on. NOW THE QUESTION IS, IS THE P28 GONE BAD AND NOT WORKING PROPERLY OR COULD IT BE THE IAC SENSOR? But the if the IAC sensor was bad on the Y8 then why when I ran the p05 witht the Y8 no engine light come on and idle was perfect. ANY HELP WOULD BE GREAT GUYS THANKS FOR LOOKING.