Rough around 500-1250 rpms

[Il Duce]

I've got an 85 325e, and the car has run very smooth since i bought it,
recently around 500-1250 rpm's, the engine seems to vibrate a ton more.
could it be a vacuum leak? i am having it looked at tomorrow, so i would like
to be semi-educated on some of the possible things wrong. TIA




-kevin

[Beej '86 325es]

I have an '86 325es with lots of miles on it. I currently have a blown head gasket and it does what you describe. Open the coolant reservoir while it's running and check for bubbles.