I have been dealing with the same problem for almost a year now. My check engine light came on and said insufficient flow. Relating to the egr valve also says 1-5 cylinder's are misfiring most likely in connection to the egr valve. I have replaced the egr valve 3 time and had the ports cleaned out a few times as well in the past few months and put fluids in to clean the carbon build up. but the problem keeps coming up. My check engine light is back on and has the same codes as before. I'm not sure what to do to anymore. Suggestions please!!

 

I have only had to clean my EGR port once in 100,000 miles. I run quality fuel and keep my car well maintained.

You may not be clearing the EGR port enough. It's unlikely that the EGR valves are even bad.

 

The issue could be in between the egr valve and the exhaust port in the head.

 

could be running rich or O2 sensor carboned up sensing the running condition. if you have thoroughly went through every component pertaining to the egr system, and are certain it is functioning properly, start with giving it a tune up if you haven't already, then check fuel pressure, and o2 sensor conditions.

 

x2.