I have a 2003 toyota echo with a cylinder 2 misfire, evaporator emission control incorrect purge, evaporator emission vent control, and evaporator emission control system leak. could this be caused by a faulty sensor or is the most possible cause a vacuum leak?

SOURCE: What is EVAPORATIVE EMISSION CONTROL INCORRECT

fumes from evaporating gas in your tank are captured and absorbed by a canister rather than being vented to atmosphere as they used to be ... when you start the car it purges the fumes from the canister and directs them into the intake manafold where they are burned with normal gas ... often over filling the tank can cause gas to flow into the canister instead of just fumes .. this may, in time,fix itself if you avoid overfilling the tank unless there is a failure somewhere in the evaporative emission control system ..(vacuum hose, solonoid, gas cap and such) .. a bad, loose or leaking gas cap can cause a problem by allowing air to leak into the canister ..

SOURCE: Service Engine and Service Vehicle lights

You can generally find a vaccum leak by pressure testing the system. Most auto parts stores sell a vaccum tester relatively cheap. Or you can take it to a shop and they will pump your sytem full of a uv sensitive die and then use a black light to find the leak. If it says vaccum leak at engine on the vent solenoid then all you need is the schematic of your vaccum system to find the solenoid and you should find your leak theoretically.

SOURCE: What is EVAPORATIVE EMISSION...Purge Flow?? Mitsubishi Mirage?

This indicates that a part of the EVAP control system is no longer fuctioning correctly. The EVAP system consists of many parts, including (but not limited to) the gas cap, fuel lines, carbon canister, purge valve, and other hoses. Try changing the gas cap first then check the rubber hoses that are visble on top of the engine. Vote "Yes" for me!

SOURCE: engine light on Codes show

Hello! Those three codes commonly indicate the followi possibilities:

The gas cap was not sufficiently tightenend ater fueling, a bad gas-cap rubber o-ring, the vehicle had the key in the 'on', or engine running, or the tank was filed all of the way up the neck.

Any one of the abope causes will set all three codes.

SOURCE: I have a 1997 Toyota

The cause of this problem is a faulty gas cap. It is not making a proper seal. Change the cap & reset light with ob11 code reader. There may possibly be a leak elsewhere but this is usually the case. Good luck!