When the egr valve died on my Blazer I ground it down flat and made an aluminum block off plate.

I put the plate between the manifold and egr valve.   Its still there so the mechanic sees it but it doesn't do anything.

Ya know, that thing never ran as good as it does now.   

That was about 6 years ago 

Part of California's SMOG test tests the functionality of these components...

In other words.....That won't fly.

GT

OK Ill take a stabe at this issue    under the Tbi the manifold has passages for egr and can clogge up causing this intermittent  problem .
Remove tbi and clean out the manifold passages replace base gaskit and do a upper intake cleaning and a injecter flush wont hurt ,have seen this with some of the early caddys with that tbi system good luck