It means that you need to replace the vacuum pot or the hose has cracks in it. Double-check the hose before you do anything else.
The pot is designed to move a plate inside the distributor when vacuum is sent to the pot from the carb. If it doesn't hold that vacuum, then it can't do it's job. More than likely it is one of the biggest reasons that you are getting poor performance and bad gas mileage.
In order for you to replace it yourself, you will need to get a stamped number off the side of the distributor and tell the person at your local parts house that you need a vacuum advance diaphragm for your car. They may need that number I just spoke of, they may not. Then you will need a flat-bladed screwdriver to get the distributor cap off. You just push down on each of the 4 "cross-heads" on the outside of the cap, and turn them 1/4 turn counter-clockwise. You don't have to disconnect any wires if you are careful. If you do disconect anything, don't break it, and remember where it came from. Lift the cap off and push it over to the side so you can see whats under it. You can change the vacuum advance now by taking out the 2 screws holding it down and then wiggling the rod out from under the flat arm it's attached to. The holddown screws may be Phillips or 1/4" hex heads. DON'T BEND ANYTHING. Reverse the procedure to reassemble it and be very careful to make sure the cap is seated completely on the distributor and the 4 cross-heads are holding before you start the engine. If you can't get the rod out of the flat arm, then it would be best if you found some help to show you how to do it.
Good luck! Successful completion makes for smiles all around!
------------------
David
newbie #4153
