Prepare a grill for low indirect heat: For gas grills (with 3 or more burners), turn all the burners to medium-high heat; after about 15 minutes turn off one of the middle burners and turn the remaining burners down to medium. For charcoal grills, bank one chimney starter-full of lit and ashed-over charcoal briquettes to one side of the grill. Set up a drip pan on the other side to avoid flare-ups. (Be sure to consult the grill manufacturer's guide for best results.)
Stir together the garlic powder, paprika
, lemon pepper, mesquite seasoning, steak seasoning, brown sugar and granulated sugar in a small bowl. Rub the spice blend
into the ribs, patting to make sure it sticks. Then place the ribs on the grill and cook, covered, 3 hours. Remove the ribs from the grill
and wrap them in foil. Set the wrapped ribs back on the grill and cook, covered, until the slab of ribs appears that it will easily break apart if bent, 30 to 45 minutes more. Serve with barbecue sauce.