The service engine soon light on our 1990 Suburban has been coming on lately so I checked the code and it comes up code 32. I believe that is related to the EGR valve. The previous owner removed the cat, but left the rest of the exhaust stock. The exhaust is shot, so I am planning to have dual exhaust installed. I have heard that EGR valves need proper back pressure to work correctly. Is this true? I have also heard that if I want to put dual exhaust on with no cat, that I should get a 'heated O2 sensor'. I had a 1989 K1500 back in the day that had dual exhaust and no cats and I don't remember having any EGR problems with that. If anyone has any experience with this stuff, please reply. Thanks.