EGR Valve

I did test the egr valvle at idle and engine stalled. I am starting to think I have a defective catalytic converter even though its two years old. I even put in BlueSky (6oz) twice ran the gas down to practically empty followed all the directions and still failed (the readings did come down a bit from 3.23 to 2.89 and the limiit is 250 this is why I and now thinking the converter is somehow defective. Have you ever heard of such a problem with a converter?

I performed the test you suggested, by teeing in a vaccum gauge between the bpt and the egr valve. I am getting 3 inches of vaccum at the egr valve on accelleration with the rpm at 2000 to 2500 rmps. When I deaccelerate the vaccum falls off and turns back on when I accelerate. I would like to know if I should take a chance and retest, this would be my fourth time at $29.00 a pop. I am still leary of the converter. I ran this test for 26 miles and it was consistant. I also contacted the manufacturer of the converter and explained the problem. He concurred with me that is possible that the converter could be bad and is covered under warranty. What do you think should I get the new converter then retest?

Would the converter cause me to get low vaccum as you suggest? According to all the manuals (Haynes - Shop Manual for 1993 manual) they said 3 inches was enough what should it be - because I'm going for the converter and I going to try your test again.

Computer problem
2000 Nissan Altima 4 cyl Front Wheel Drive Automatic

Where is the EGR valve located on a 2000 Altima? Engine check light is on?

The code is P1400 per Autozone, EGRC solenoid Valve?

What do you use for air flow? Do this with the engine running? Use an external power source of 12Volts?
Please clarify/Thanks!