How do you find a vacuum leak in your 2000 sable?

First inspect every single vacuum line connection, looking for cracks and loose connections. If you find no obvious defects, then Start the engine and then using a spray can of WD40, spray all of the connectors where the vacuum lines are connected and the length of the lines. When you hit a leak, the engine will change revolutions as the WD40 is sucked into the intake and burned. You will notice the difference. You can use FI Cleaner, but WD40 is much safer. If you still do not find the culprit, take a close look at the Brake Booster vacuum diaphragm.
First inspect every single vacuum line connection, looking for cracks and loose connections. If you find no obvious defects, then Start the engine and then using a spray can of WD40, spray all of the connectors where the vacuum lines are connected and the length of the lines. When you hit a leak, the engine will change revolutions as the WD40 is sucked into the intake and burned. You will notice the difference. You can use FI Cleaner, but WD40 is much safer. If you still do not find the culprit, take a close look at the Brake Booster vacuum diaphragm.