I got stuck in an hour long "parking lot' type traffic jam last week. My 88 300E ran warm...not all the way hot, but almost 3/4 of the way up the temp guage.

Since then the car runs rough on a cold startup.
I had noticed over the winter a 'squeeking' sound from underneath the drivers side rear seat (where the rear headrest vacum system is located). Last fall the center vents stopped outputting air when I stood on the accelerator, and now do not output any air at all. I have not had time to address either of these issues. Are either of these systems connected to the main engine vacum system?

If not, what likely vacum leaks might be exascerbated by running warm? I have some interesting noises/sensations when fully depressing the brakes (intermittent). Would the brake bomb/hose be a likely candidate? The guy I bought the car from did state that he 'freed' a sticky caliper before he sold the car to me. I am not sure if what I sense is a poor repair job on this caliper or a vacum problem.

I have replaced all the engine vacum lines as well as the one to the trans modulator, along with a valve job, head/intake gasket,new injectors, resoldered the OVP, new temp sensors, etc.