Looking for vacuum leak
 

I searched the forums and people have said something about a vacuum leak that can cause rough idle on the M104 engine. Where exactly is the vacuum leak from? Is it like a tube or something?

spray starting fluid all vacuums during running, if the idle changes you got a leak, thats the way I always check for a vacuum leak on all cars, don't worry the starting fluid will vaporize quickly, so no need to clean it up, hope that helps

Go easy on the starting fluid. A loose spark can ruin your day.

Sixto
91 300SE
81 300SD

What is starting fluid and where can i get some?

Starting fluid is a volatile fluid that helps get stubborn engines started. It's commonly used on carbureted engines in cold climates. You should be able to find starting fluid at any auto parts store. It comes in a spray can like carburetor cleaner or brake parts cleaner... either of which should also work in tracking down vacuum leaks. KEEP THE SPRAY AWAY FROM SPARK PLUG WIRES AND THE COIL!

Sixto
91 300SE
81 300SD