My CEL would go on and off randomly when i first did my swap....i was still using a P72 GS-R ECU. I looked over the lines a couple times then sat aside the following saturday to make it right since the code was something to do with that. Within minutes i saw that on that was capped off shouldn't have been and one of the lines was crossed...i ended up buying a T from napa and made them right (what i thought to be anyways) and the CEL went off...got the P73 ECU and it's still been fine.