GM Service Manual Online
For 1990-2009 cars only

Problem

Action

The engine is not performing efficiently, possibly because of plugged or restricted injectors or high altitude conditions.

Refer to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls.

The converter parts are broken.

Replace or rebuild the converter assembly.

Refer to applicable Allison Transmission Service Manual.

The vehicle stalls at speeds of 50 percent of normal, which implies a freewheeling stator.

Replace or rebuild the converter assembly.

Refer to applicable Allison Transmission Service Manual.