If you are not prepared to remove the distributor, you would probably be better off taking your vehicle to a mechanic. A mechanic would have a vacuum pump to check the diaphragm. If the chamber is indeed bad, and there is a good chance that it is, the distributer will have have to be removed to install a new vacuum chamber. These chambers are obsolete, but they can be found. Make sure a chamber is available before you have anything done.
