I have the MIL light on my 1999 Tahoe with the 5.7l Votec. The code is comming up EGR return circuit low. Is there any reason other than the EGR being defective that this code should come up, or should I just replace the EGR.

Ok, found the problem, the EGR was stuck. Carbon had built up and it was just welded shut. Used a screwdriver to loosen and clean out, some carb spray and the code went away. Heres a new one on me, after fixing the EGR I got a code of 1354. Turns out after the engine rebuild, I didn't set the timing, the computer was throwing fits even though the truck ran fine.