If that car has an egr switch/over valve, check the vent on the valve for blockage.
When a sw/o valve is de-energized, the vent lets air back into the vac line. If it doesn't, the egr can not pull back to the closed posistion because of the vac. holding in the line.
[ kind of like when you hold your finger over the tip of a straw and pull liquid when lifting it.]
That goes for most switch/over valve set -ups.