I keep getting a P401 code EGR flow insufficent on my 2003 honda civic 1.7 on 2003 Honda Civic

I have cleaned around the EGR port several times but still getting the code. After cleaning I can run the car for about 30 minutes but will still get the code. I have even bought a new one but still getting the code. What else could be wrong.

Asked by for the 2003 Honda Civic
the amount of vacuum to the valve. hondas are common for carbon clogging the vacuum ports to the egr. have a shop verify this.

What ports are you talking about this only has an electrical connection to the top of the valve..
when you remove the valve, there are 2 ports. one is exhaust and one engine vacuum. the engine side tends to clog badly with carbon.