Q: is a purge valve solinoid the same as a evaporation vent soliniod?

In the EVAP system, the purge valve and the vent control valve are separate parts with different functions. If the gas mileage you are getting is very low, there is probably a fault in addition to the EVAP system fault. The only way to know for sure if the purge valve is really faulty is to test it. Reference to the purge valve in a diagnostic trouble code description is not sufficient to conclude that the valve is faulty; it has to be separately tested because there are other causes of the code setting. The causes of the poor gas mileage have to be separately investigated but some possibilities are overly rich operation, failing oxygen sensors and even other vehicle faults such as dragging brakes or underinflated tires. If you desire that the problem you are having be diagnosed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a check engine light diagnostic and the responding mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.