Surge Downhill with Cruise Control On - Normal Characteristic - keywords chuggle decel decelerate down engine erratic flare
| Subject: | Surge Downhill with Cruise Control On - Normal Characteristic |
| Models: | 2004-2005 Chevrolet Colorado |
| 2004-2005 GMC Canyon |
| with 2.8L Engine (VIN 8 - RPO LK5) |
| or 3.5L Engine (VIN 6 - RPO L52) |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
On rare occasions, a chuggle or surge may be experienced while descending long grades with the cruise control on at highway speeds. Typically, this is more likely to occur in mountainous regions.
Recommendation/Instructions:
If this does not occur with the cruise control off or when traveling on flat road surfaces with the cruise control on and there are no DTCs stored, no repairs should be performed since this is a normal characteristic of the vehicle. To prevent this from occurring, disable the cruise control when descending long grades.
Additionally, the "using cruise control on hills" section of the 2005 model year owner's manual states: "When going downhill, you may have to brake or shift to a lower gear to keep your speed down. Of course, applying the brake takes you out of cruise control. Many drivers find this to be too much trouble and don't use cruise control on steep hills." The 2004 model year owner's manual does not contain a cruise control section.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
