Yes, that is the reason. Without an airpump, the catalytic converter is fairly useless at idle and the lower rpms.

 

RICK - i am also getting pretty strong exhaust smell in cabin and still trying to find a solution to that.

Mahjik - regarding the lack of air pump, this is a strictly FD/rotary type deal? I've driven open exhaust cars and racecars and the fume is no way near the fume I am getting from my street-modded FD.

For those that have the same issue and looking for solution, I think here are a few ideas/solutions posted so far

- get the car tuned
- replace turbo manifold gasket (not easy to do!)
- hook up air pump

 

The rotary is fairly inefficient with its combustion cycle (this is why so many people have issues passing emission testing in states where the test is required). What doesn't get burnt, has to come out somewhere.