Oldsmobile Bravada P Codes (Powertrain)

I Got The Error Code P0420, Catalyst System Efficiency Below Threshold Bank1. I Know That I Have A Possible Exhaust System Leak, But Also...

Vehicle Stalls/shuts Off When Coming To A Stop. Code Is P0300 Has Back Fired Once.

Hello, After P0440 Code Started Showing We Replaced Gas Cap And Fuel Filler Neck, Which Was Badly Corroded, And Fuel Pump. Code Was Going...

Engine Light Came On. Lost Speedometer, Transmission Now Shifts Erratically. Pulled Codes, P0502 - Checked All Breakers, Replaced Vss...

Im Getting A P0410 Code And I Desperately Need To Pass Deq What Is My Best Plan Of Action

Figured It Was An Emissions Thing, Like The Po440 That Keeps Appearing Yet Doesn't Affect My Mileage. But This P0449 Keeps Coming Back...