Oldsmobile/Buick Repair: mercury rough idle, mass air flow sensor, mass air flow

Question
I have a 1996 Mercury Sable w/ 3.0L V-6. It idles rough with a low rpm and has poor performance during acceleration. I have replaced the plugs, wires, coil pack, mass air flow sensor, and oxygen sensors. The mechanic I took it to said that the diagnostic computer said something about the egr system and possibly the catalytic converters. I wanted to get your input before I go and spend a bunch of money on the converters.  

Answer
hi jason, well sounds like convertor may be plugged or possibly just the egr valve is bad and this is the usual prob and the simplest to repair egr .you can take to an exhaust shop and have back pressure done on converter.egr is very easy to replace.but normally what will happen on this car is the rubber hose going to the egr transducer normally will close or burn in two you will be able to see this at the egr .these are your options ty please vote for me billymac