on my 1996 maxima, my check engine light is on, and reads the code P0400, which is a malfunction in the EGR flow. What could this problem be, and how can i go about fixing it? I doubt that it is the EGR Valve itself, because that was replace about 6 months ago. anything you can tell me would be helpful.
thanks

 

clean and or replace the two egr tubes this is what i did my car felt like a new car all my stumbling went away and cel turned off.