Car running rough at idle; high carbon monoxide

1993 Oldsmobile Bravada, 141,000 miles, automatic, AWD. Help. Please. Car has been running rough at idle for three years. Couple years ago, EGR valve was cleaned and ran well for about 6 months. Computer was checked - OK - and prom was replaced two years ago. Very fouled spark plugs replaced three weeks ago. Last week, spider (fuel injectors, fuel pressure regulator, etc.) Was installed. Fuel filter replaced. IAC valve OK. Intake manifold appears clean. EGR was replaced 9 months ago, and again replaced last week, even though appeared OK; shop even tried bypassing the EGR by plating off, but no difference. Compression check run on engine last week also, and all appears OK. Car still runs rough at idle, and shop has no idea what's wrong.

Just had the vehicle emissions-tested last Friday. Carbon monoxide is 69; allowable 25. Not good. Any ideas?

P.S. Guys, I'm trying to make a donation, but your site won't take my credit card(s). Keeps saying I have a Paypal account, which I has set up years ago, but was never able to make work. So, I'd love to give you a donation via credit card, but looks like I need help with that, as well as with my car.