Need HELPP Understanding!

I have a 2000 Max with 55k on it and I got Service Engine Soon light on. I got the Codes and I know what they say, I just dont know what the codes mean. Codes are P0455 and P1448, I have no idea what they mean and how expensive something like this could be.,.and i did tighten up my fuel cap. If anyone could help thanks.

well im not sure for your year model, just drop by autozone and let them check the codes and they will tell you. all i know to do