My 1994 E-350 Club Wagon with the 460 has an open vacuum tube right next to the radiator on the passenger side. It is kind of oval in shape and clearly runs down then back to the motor. My question is what is supposed to be attached to this at the top, as it surely shouldn't be this way. I recently bought the van and it dual fuel propane and gas. I get some surging of the engine when it is cold and I am thinking this open vacuum line may be part of the issue. Any help would be greatly appreciated.

 

plug this vacuum line if you can't find a component where it plugs in. otherwise do a complete search.