I have checked for movement of the EGR valve and it is moving and it holds vacuum. I also checked for presence of vacuum from the throttle body line and it shows vacuum when the throttle is opened. BUT -- when I apply vacuum to the EGR valve when the engine is idling, there is no difference in the way it runs. And as you suggested, I would expect the engine to run poorly. Its not doing that. So The actual exhaust gas circuit must be plugged or the valve is not really opening. So my next step is to pull the EGR valve off and see what is going on and check to see that the passages are clear.
I am just praying that my cat is not the problem. Is there any way to tell if the cat is working or not?
BTW these new emissions tests are really tuff. They run the car at speed on a dyno at about 25 MPH and measure the emissions under actual driving conditions. Last year it was only measured when the engine was not under load.
I got too many cars!! Insurance eats me alive. Dave
78 Corvette Stingray - 3k
82 242 Turbo Volvo - Manual - 270k
86 300e 5 speed manual - 210k
87 420sel - 240k
89 560sl - 78k
91 420sel - 205k
91 560sel - 85k
94 GMC Suburban - 90k
97 Harley Davidson Heritage Softail - 25k
00 GMC Silverado 1 ton 30k