Codes

I,m trying to firgure out My 92 Blazer it has code 12 and 45 I have all ready replace the oxygen sencor and map sencor but it still does not run right and it startes real hard the two codes that are still present are the two that I started with 12 and 45 could some one tell Me what these codes are
Thanks 70D

Code 12 is normal with key on and engine off - will always be there - ignore it. Code 45 indicates Knock Sensor condition.