[Guest (MBNZ)]

My 300CD won't shut down unless I lock my door. I know this is a vacuum problem, but can anyone take a stab at where the problem is from the symptom.

 

[Guest (MBNZ)]

sounds like you have a vaccuum leak. check the connection to the shutoff valve which is a vaccume line attached to the the back if the fuel injection pump - should be just forward of your oil filter canister. if that is ok then you need to find where the vacuum leak is and repair it.a vaccum gauge like a mityvac is the tool you need to analyze the system step by step.<br> good luck