Engine - Low/Rough Idle/Low Speed Surge
Information IB05-01-S001Unstable/Rough/Lumpy Engine Idle and
Low Speed Vehicle Surge, Random
Disturbance or Vehicle Shudder
Light Duty ASCENDER 2003 Information ENGINE 01/01/05
Light Duty ASCENDER 2004 Information ENGINE 01/01/05
Light Duty ASCENDER 2005 Information ENGINE 01/01/05
Unstable/Rough/Lumpy Engine Idle and Low Speed
Vehicle Surge, Random Disturbance or Vehicle
Shudder
ISSUE DATE: JANUARY 2005
Affected Vehicles
2003-2005 Isuzu Ascender (US) models equipped with 5.3L V8 engines (VIN P or M).
Service Information
Some owners may comment on an unstable, rough, and/or lumpy idle condition. In some instances a low speed vehicle surge, random disturbance and/or shudder may be experienced.
The low speed vehicle surge, random disturbance, or shudder may be felt by the driver while the vehicle is creeping slowly forward under partial brake apply or coming to a stop with a partial brake apply, with the throttle closed at less than 3.2 km/h (2 mph). The sensation is similar to a vehicle having extreme lateral run out on the front rotors, although there is no sensation in the brake pedal. The condition may be more pronounced on a slight incline or while using the vehicle to tow a trailer and when the coolant is still cool.
At present, there are no mechanical, electrical or fuel related updates that will eliminate these conditions. These are normal vehicle characteristics and no repairs should be attempted.
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