tahoe AWD power loss 1994 Tahoe with all wheel drive and stability control: occasionally, when accelerating from a stop, the engine loses power, as if traction assist is kicking in, except the wheels are not slipping. Also, the "Service Tire Monitor" message comes on now and then. There is a howl in the front, seems to be coming from the left wheel area. Had new bearings installed in front differential but didn't help. Wondering if the GM all wheel drives have similar trouble, especially the engine cut-down as described above. Mechanics I've consulted don't seem to know much about the GM all wheel drives.