I have read a few threads on this problem which seems to be common. While vacuum leaks and fuel pressure may be the cause, I found something completely different - a wheel speed sensor was dirty.
In this 2006 Suburban 4WD the wheel speed sensors not only activate the anti lock system but also link to the throttle subroutines in the computer. With the wheel sensor dirty, it caused the computer to think the wheel was slipping and issued a 'traction active' message and locked the throttle at idle ignoring the accelerator pedal entirely for several seconds only regaining manual control at 7mph.
To fix this the rotors have to be removed and sensors cleaned or replaced. Autozone has repair guides and replacement sensors as does ebay motors.

If this happens it is a serious safety issue as you can easily stall in an intersection! A fast work around may be to remove the anti lock fuse but I have not tried this myself.