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.

Yep, look at this link for info:
http://www.obd-codes.com/trouble_codes/generic/p0440-evaporative-emission-control-system-malfunction.php

Sweet...............thanks for the link!

GAs Cap. They just plain wear out after 130k miles. Thats about when mine needed replacing. Its a cheap thing to try before doing anything major.