engine wont pass emissions

I have a 1986 Chevy S-10 2.5TBI 4x4 and it won't pass emissions. I'm testing about 1.5 over the limit, all other tests are good. I have replaced practically every component of my ignition; distributor, dist. cap, rotor, plugs wires. I've traced every vacuum line and sealed all leaks, there were about 5. The truck won't throw any codes either. I've tested most sensors and valves that determines fuel delivery and they all seem flawless. The truck is perfectly driveable, I think it only runs rich from about 900-1600 rpms, no tach, just going off sound. I need to pass by tomorrow afternoon, WHAT DO I DO??!

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