03 9-3 turbo 5spd: intermittent engine vibration and bogging

[zacob]

This car has been a nightmare!
The turbo blew out July 09. I had the turbo rebuilt, the mechanic didn't get the balance correct on an internal part and the turbo blew again in January 10. The mechanic replaced the turbo as under warranty. Both times I did the removal and install.

Now there is a distinct engine vibration and bogging down of the motor under certain types of acceleration. Typically this occurs after a down shift, or after you have let of the gas a bit and then re-apply the gas. It occasionally will occur on takeoff. I don’t hear any spitting or coughing out of the engine, it is more the sensation of a violent shake at the engine accompanied by a complete lack of power. After a second the vibration is gone and power comes back.

In the noted two turbo repairs I didn’t replace the O2 sensor or the Catalytic converter, time and money aren’t falling from the trees.

In looking up information on these items failing the symptoms don’t seem to match what I am experiencing. Because I didn’t replace them I am inclined to think they are the issue. But I don’t want to drop the coin to find it’s not the proper fix. What other things do I need to be looking at?