Evap system purge flow and EGR flow are two different things.  Evap
system captures the gas form of gasoline and stores it in a canister.
The purge flow routes this gas to intake to burn.  EGR is Exhaust Gas
Recirculation which routes some exhaust back to intake.  Exhaust cannot
be burnt so this will reduce engine temp and NOx.

There is a solenoid to open the evap purge flow, though I don't know
where it is in your car.  You may follow the fuel line from the tank.
There should be two same size, one for feed and the other for return.
Then there is another bigger/fatter line.  That is used for evap.

The clogged line cleaned last time is probably the EGR pipe, routed from
exhaust, back to rear engine, then into intake.  That pipe is pretty
thin and needs clean up after these many years.  The EGR flow code
should be P0400.