I just acquired a 1985 528e and it has started doing weird things. I think I have a vacuum leak somewhere because on occasion when in park or neutral the idle will be all over the place and when this is happening I also have increased brake effor (vacuum assist brakes so it all makes sense).

What is really weird is that when this stuff happens I also lose most guages on the instument cluster (Fuel, Tach, Coolant Temp....everything except the Speedo). How can this possibly be related?

beleive me i have one, its nothing but a electrical, sensor, bad ground, people guessing nightmare. i have done nothing but throw good money after bad into this piece of s***. I keep this car and gave away a gread GM. good luck with your car. p.s my advise get rid of car.

I just acquired a 1985 528e and it has started doing weird things. I think I have a vacuum leak somewhere because on occasion when in park or neutral the idle will be all over the place and when this is happening I also have increased brake effor (vacuum assist brakes so it all makes sense).

What is really weird is that when this stuff happens I also lose most guages on the instument cluster (Fuel, Tach, Coolant Temp....everything except the Speedo). How can this possibly be related?
Do you have a Bentley manual, so that you can follow their trouble shooting suggestions and also see the electrical schematics for troubleshooting your electrical problems? Electrical contact problems due to vehicle age cause all sorts of issues, as do vacuum leaks due to hoses and gaskets that are now leaking. I've had my 1983 528e since new and it is bulletproof, which yours can also be with some work. Check my web site for examples.
-Rod