hi, last night when i was coming home. my 2002 frontier desert runner ses light came on. and today i got the codes pulled. p0455 and p0328. one is knock sensor other is a large emission leak. and i am going to be doing the relocate mod for the ks, to take care of the p0328 code. but i never had to deal with a p0455 code before and would like help in finding out what is cousing it. i have re tighten the gas cap but cant think of what else it could be. and i also will be running 91 octane until i can get the ks relocate done. any help would be appreciated.