The vehicle is a 1980 300SD, 116 Chassis with nearing 300K miles. My problems began with a slight delay in the engine shutting off with the key, and has progressed to no door locks and I have to raise the hood and manually shut the engine off. I have also noticed the engine is running rough at idle, but smooths out at about 1000RPM. I intend to troubleshoot the vacuum system, but can't tell from the descriptions which of the guides I should purchase: the vacuum door lock one, the my engine doesn't shut off one, or the larger, apparently more comprehensive diesel survivor's guide. I know which one would logically be the best, but am budget oriented, and can't make myself spend money that isn't necessary. Some independent party please provide guidance.