'89 Exhaust

Okay, so I have a 1989 Chevy Sub with a 350. While on the highway, I was doing about 140km/h in order to pass, and noticed a sulphur smell. When I got to where I was going, the exhaust smelled VERY strongly of sulphur. This only happens when I get my SES light on after being on the highway. This CAN'T be a good thing, and I still get my code 32 and code 45. Is this related to the EGR? Thanks

Well the egr is in my hands and i can hear the carbon rattling around inside. Any way to fix this? Thanks

Buy a new egr valve. No other way to fix it.

Yeah, that's what I've been hearing. But also, I went to Bumper to Bumper and the guy there told me that it could also be my MAP sensor. Is there any way to know, or is it more likely the egr? The other part is that since my engine has been running rich, the guy at BtB figures that it screwed my catalytic converter. Is this likely? Because he figures that's where the sulphur smell is coming from. One of the mechanics can put in pipe in place of it for a hundred bucks. Any advice on this would be appreciated.