dabbott88

My check engine light has been on for about 4+ years, I clear the DTC's every year to get it inspected. Everytime I check I get the P0455 code and the ocassional other code, most recently B2961(I believe this had to do with some failed car jackers). The other codes do not reappear, the P0455 code is the one I am concerned about, First of all should I be concerned, could this be a sign of an actual problem, or just emissions problems, or could this potentially lead to more serious problems. From what I've already found on this code it is a problem with the evap/vacuum pressure. My gas cap is fine, even tried a new one with no change. A couple things I notice that may or may not be related. First I can hear alot of pressure being released when I remove the gas cap, second when I park my truck and get out I can hear a somewhat fast series of creaking/popping sounds coming from my fuel tank, as if it is expanding or contracting(I usually only notice this at the end of the day). Any help on this subject would be greatly appreciated. I mainly want to know if something needs to be done about this, if I can get away without spending money, thats the route I want to take.
Thanks,
Daniel