My wife�s mystique just started making a strange noise from the EGR. It can either be a hissing/sucking or something with the exhaust noise. I got a EGR insufficient flow code so I checked the TB and did a test on the EGR. The TB passages were fairly clean and the EGR appeared to functioning properly. The car is driving normally but getting slightly lower gas mileage 22 instead of 23-24. It has also been throwing cat inefficiency codes for a while now. I did the seafoam spray again this morning but this didn't help with the noise any. What else can I look into and has anyone else had this problem. Also the DPFE is almost new and not giving me the typical excessive flow code when it has failed.
