I have a 1985 735i auto with a couple of problems. when i start the car the revs jump up and down erraticaly from 400 to 800 then settles down after a while.But when i make a sudden stop or depress the gas pedal the engine almost cuts out. I have been told its a vacum problem but i have no idea what to check. My second problem is that occasionaly the car will not start.Nothing happens the relays click the waraning lights come on then after a few while it suddenly starts. Any advice would save me a lot of grief.Thanks