Catalytic Convertor problems of the 2001 Chevrolet Suburban

Gas fumes can be smelled inside and outside the vechicle when outside temps reach over 105 degress. Has been witnessed by two Chevrolet service managers and head mechanic. Has been serviced 5 times by bradley cheverot and I have been told that the regional rep has stated that the fumes both visable and odor are very normal. Both the service manager and head mechanic have stated that they feel the car is not safe and would not put their families in my vehicle. The vechile smells up my entire home with gas fumes and has to be parked outside of the garage. The engineers have asked that a couple of parts be changed on my vechile to pasaify me, but that it is probably my fault, I must have over filled the gas tank - and I was asked "just what exactly are you doing mrs. Anderson to cause this problem?". I have been told by the dealership that several cars in las vegas and texas have reported the same problems.