I'm not sure, but maybe it's this.
Here is the Bulletin- it is a normal condition to protect the transmission:
Engine Miss on Acceleration After Shifting from Drive to Reverse - Possible Characteristic - keywords 1 abuse accel accelerate cut cutoff cylinder fuel hesitate hesitation in management misfire normal #PIP3485 - (Jul 1, 2005)
Engine Miss on Acceleration After Shifting From Drive to Reverse - Possible Characteristic
2005-2006 Chevrolet Colorado
2005-2006 GMC Canyon
2006 Hummer H3
with an Automatic Transmission
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
A brief engine miss may be experienced if the transmission is shifted from drive to reverse and then accelerated when the vehicle is still moving in a forward direction. If monitored with a Tech 2, it may be noted that a few engine misfires are present on cylinder 1 during the concern. It may also be noted that other vehicles in new car inventory exhibit the same concern. This is the result of a torque limiting feature to prevent transmission damage.
Also a lot people with the "dragging brakes" are actually feeling the All Wheel Drive operation. It's the same feeling as driving a truck in 4 wheel drive on dry pavement.
|