I have a 1994 z28 camaro with headers that is running very rich. The car has a exhaust leak on the passenger side header which seems to be the culprit. It seems like every 4-6k miles my ses light comes on and it always has something to do with emissions (egr or 02 sensors). Is this primarily because the car is running quite rich?

 

You pretty much answered your own question. Fix the exhaust leak first.

 

What is the EXACT code?

An exhaust leak before the O2 sensors will cause it to run rich, as will misfires, or faulty O2 sensor(s).