I recently installed a P28 into my 94 cx hatch running a D16Y8 motor on a P05 ecu. It was not wired for vtec so I did the wiring for the vtec solenoid and converted my car from a 1 wire O2 sensor to a 4 wire so that the P28 would work. After I completed both of these things I fired up the beast and I was running in limp mode with my CEL on. So I check the code and it was a 14: 14- Accord Civic CRV CRX Del Sol Odyssey Prelude 88-98 88-98 97-98 88-91 93-97 95-98 88-98 IAC Valve (Idle Air Control) defective circuit or unplugged / defective sensor And my idle was really low so I cracked out the screw driver out and adjusted the screw that opens and close the butterfly plate I think. This brought my idle up but now when I drive it is fine when above 2000 rpm but at about 1500 it bounces back and forth, also when I am giving my car gas and I let off of it, it will jolt. I checked the plug on the sensor and it is fine. And the funny thing is that I was not getting this CEL when I was running my P05, is this because the P05 doesn't use this sensor or what? I also thought that some how I damged the sensor working on the the other wiring so I put my P05 back in and the CEL went away.