The purge control solenoid is located on the engine (in between the two cylinder heads. Test on the solenoid are needed before assuming it is bad, it is easy to replace. If the valve it could cause a rich running condition if it sticks shut the evaporative emission system wont allow gas vapors in the fuel tank to be burned by the engine allowing for less emitted pollutants. If it is something you plan on tackling yourself and need test information there is a company that independent auto repair shops "buy" their information from that offer a very reasonable service to do it yourselvers. You can get a one week subrcription or year subscription very cheap. The information is year make and model specific repair procedures, service bulletins, component locations, wiring diagrams ect.... great quality information same as the professionals have ,much better than generic workshop manuals from parts stores, much cheaper than the factory manual try http://bit.ly/mitchell_repair_manuals_online and get an online repair manual subscription.