DTC 4-4-3 is a problem with catalytic converter efficiency for a number of reasons. Efficiency is monitored by the ECM measuring readings between the front O2 sensor and the rear O2 sensor. The book says fault can be caused by Uneven compression, Air leak in the intake system, Air leak in the exhaust system, Incorrect fuelpressure, defective cat converter. Did you get a 4-3-5 or 4-3-6 code ? This would indicate one of the O2 sensors bad. Is the motor still running rough ? If it smooths out try clearing the 4-4-3 code and see if it comes back. Check for a loose vacuum hose. Since you are now seeing odd readings on your Turbo gauge look closely in that area. You may end up doing a compression check if you can't find anything else.

Mike