This only applies to Pre-Facelift V6 Engines (and very early Facelift Engines) prior to any of the DriveByWire setupsAs a few people have said on here, blanking off the Exhaust Gas Recirculation Valve on the V6 can sometimes improve Idle, and in general, help relieve a few other problems which may spring up.
Now the usual way is to get a tincan and "Cut" a template to blank it, however, Vauxhall do actually supply a 'Blanking Plate' which will fit! It's not listed on the Omega section of the EPC, and is only listed on other vehicles, but it will fit.
So, if you want to blank your EGR valve, you need to order the following parts:
90467547 - GASKET, EXHAUST GAS RECIRCULATION VALVE

12554606 - COVER, VALVE, EXHAUST GAS RECIRCULATION
Ensure the Engine is COLD1) Unplug and Unbolt the EGR which is on the left hand side of the engine.
2) Clean any existing gasket or muck which may be left.
3) Fit the gasket and seal plate. Place the gasket onto the EGR mounting bracket/pipe (which comes from the exhaust manifold & goes to the inlet), then place the sealing plate onto the gasket.
4) Position the EGR valve ontop of the sealing plate in the same position it was previously, put the bolts in and tighten them up.
5) Re-attach the plug to the EGR valve.
