EGR trouble...still

My 96 1.0L metro keeps throwing the low EGR flow code. When I first removed it both passages and the valve were plugged with carbon. I have cleaned the passages, and the valve, replaced the vacuum hoses, checked the AIT sensor, and engine temp sensor. I have used compressed air through both passages confirming they are open. The EGR valve operates when I apply vacuum to the diaphram. I have checked voltage to the solenoids that regulate vacuum to the EGR valve itself, voltage is erratic at best; also another puzzling fact is that when I remove the EGR valve, one port has vacuum, but the other port is neutral, I would have guessed that it would have positive pressure. Thanks in advance for any help.