1995 GMC Jimmy carbon build up

1995 GMC Jimmy 4WD mileage: 126,000. My truck has been experiencing problems caused by carbon deposits in the EGR Valve. We have replaced the valve and cleaned out the valve many times, including, most recently, three days ago. However, the truck stalled again and when we checked the EGR valve, more carbon deposits had built up and had to be removed. I understand that the GM Vortec engine has a history of carbon build up problems. Is there anywhere else we should check for carbon buildup that's already in the system, or anything we can do to prevent the carbon buildup from occurring so frequently? Thank you.