This is one I vaguely remember from my childhood. I only remember a couple scenes. I think there was an archaeologist exploring some pyramid ruins in the desert, and maybe unlocking a curse of some kind. One scene I remember (this is going to sound odd, and I am maybe not remembering accurately): a character is in a vehicle (maybe a jeep or truck) in the desert; he removes the cigarette lighter, and sand begins blowing out of it, burying the guy and the vehicle.
Another scene was under the pyramid, I think, and near the end; there was a river or waterway with a boat and a gate across the water; I think this was near the end and going thru the gate took them to an underworld kind of place.