newbie need info with a B18c1 swap

ok so recently i did a b18c1 swap on my 93 SI hatch....mostly stock jst has a skunk2 manifold...my question is if i run a stock p28 ecu how would affect me...reason for question is bcuz took it for a test drive nd it runs like crap...engine stalls when is between 2000 3500 rpms nd then it runs ok