My wifes mystique has been spitting out codes a lot lately. The cat codes weren't bothering me but now that the 402 (EGR Flow Excessive) code has popped up on two of the occassions with both cat codes I am starting to wonder what to look for. I looked for bad hoses to the DPFE. They all looked good and I can't find any intake leaks. Gas mileage is normal and performance is normal. The DPFE was replaced within the last 2 years. Any more suggestions.