i have a 1997 Stick ls integra and i swapped a 98 ls motor into it. i got a code miss fire cylinders two and four. so i toke the distributor off the 97 motor and it said the same thing. i changed the ecu from a 37820 - p75- A03 to a A04. and the code went away. can someone explain what the difference is or why this worked and the other one didn't?

 

just got the check egnine light again. my compression is on point threw all of my cylinders. i just got my timeing belt replaced two in the past two weeks to be 100% sure that wasn't it. and i'm still getting this code can anyone tell me what i'm doing wrong?