Good morning my name is Roy and I will assist.
It does sound like the cat converter is the issue but you can check it a couple of ways.
You can get a back pressure gauge and install it where the upstream O2 sensor is located and measure the back pressure.
If you dont have a back pressure gauge then unbolt the front pipe from the manifold and drive the car and see what happens
Yes, there are models that do not have EGR valves. The 2006 is one for both the turbo and non turbo models.
Roy
Thursday, December 21st, 2017 AT 3:53 AM