GM Service Manual Online
For 1990-2009 cars only

Problem

Action

Engine not performing efficiently.

Inspect for the following conditions:

    • Plugged or restricted injectors
    • High altitude conditions
    • Dirty air filters
    • Incorrect fuel/valve timing
    • Throttle linkage broken or not properly adjusted
    • Electronic engine controls condition

Refer to the Engine section of this manual.

The following specific sections should be helpful in defining the problem:

    • Refer to Diagnostic System Check - Engine Controls in Engine Controls - 6.6L (LB7).
    • Refer to Diagnostic System Check - Engine Controls in Engine Controls - 8.1L.
    • Refer to Symptoms - Engine Mechanical in Engine Mechanical - 6.6L (LB7).
    • Refer to Symptoms - Engine Mechanical in Engine Controls - 8.1L.

Stall speeds of 33% of normal implies freewheeling stator

Replace converter assembly. Refer to Torque Converter Replacement .

Engine smoke controls

Compare lugback to static stall speed.

Incorrect torque converter

Install correct torque converter. Refer to Torque Converter Replacement .