97' Blazer. 130k miles 4.3ltr. Just got the code PO440. I know it means EVAP EMISSION CONTROL SYSTEM MALFUNTION. Where is the most likely place to start on this problem. I've made no recent repairs lately either. I did a search on the forums and looks like gas cap replacement and vent control valve maybe? Where would you start? Just want to clarify on these possible fixes for my current vehicle. Thanks.
