Hello, I (my wife) has a 85 300 Turbo Diesel that at times will run on and then will die (engine stops running) after @ 5 seconds of the ignition being turned off. At first I thought it was when it was cold outside but it is intermittent and I would like to fix the issue. It also seems like when it does this, the door locks don't always work so I assume it is vacuum related. Any tips, advice or suggestions are welcome.

I am more familiar working on Jeeps but not afraid to spin a wrench.