I was going to make this similar thread a few months ago. I have a one year old Kluger Grande. Right from the beginning I have been experiencing this rotten egg smell permeating the cabin from time to time. Initially I thought one of the kids has farted. Somehow no one admitted to it. Then I noticed that it seems to occur in certain area especially the on ram of the free way. There is some forest there so I initially thought it was related to some swamp gas or whatever. Later I worked out that it is related to hard to moderately hard accelation. eg going up on ram, over taking, going up a hill etc etc It is much worse if the vent is in "recycle" mode. With the vent opened it is not as bad but if you are going up a hill for a prolonged period you will still get the smell coming in. The car is in the service department the second time now. The first time they told me that the rotten smell is from the catalytic converter. The fume got through the tail gate. They took out the trimming and fixed some sort of plastic sheet in before reassembled the trimming. They were hoping that it would reduce the fume from coming in. Well, it has helped a bit BUT the bloody smelly fume still coming in if you press the accelerator hard enough or long enough. Been driving for 30 years and I have never experience this in any other cars. I told the service manager that leaving the vent opened is not an option. The air pollution and fume from other cars are bad on the road. It also make the air cond much less efficient. I have a feeling that the fume is coming through not just from the tail gate.