| Re: VSC, Check Engine, Trac Off ?????????
The returnless system does help to keep the temp inside the gas tank low, but as does not make it any difference as far as EVAP system configuration. The basics of vapor purge have not changed much since 70's. The ECM got much smarter in monitoring the system's performance though.
With Purge VSV (Valve at the air filter housing) you can check the resistance between the terminals: should be around 25 Ohm. Supplying the battery voltage to the valve's connector should make it click open. If it doesn't then spraying some WD40 inside the hose fittings and letting it soak may help. | 
