88 K5 TBI 350 Code 32

I am having a problem with the ECU setting a code 32. This would indicate an EGR problem? The EGR valve has been replace. No Change. The code is set after about 10min of driving. Consistently!
I have also replace the EGR vacuum control solenoid. Still no change!
Someone please help me out here. What am I missing?
I will be changing the O2 sensor this evening.
Thanks in advance for your inputs!