Improper flow EGR valve
I have 2003 Chevy impala Base 3.4 engine that the engine light stays on. The car runs great. I have gone to Auto Zone three times to have them check the faults to see what the problem is. Each time it has come back improper flow EGR valve. I have replace the EGR valve and removed and clean the pipe down to the exhaust manifold twice. I started the car last time and removed the pipe that goes down to the manifold to see if it was exhausting without a clog and it seem to be clear. I have had Auto Zone reset the CPU and have remove the battery post and reinstall to reset the fault. It seems to work until the engine becomes warm, then the engine light reappears. What else can I do? The light has been on for two years, the car runs fine. The only reason why I need to fix this is because the vehicle will not pass Maryland emissions.