Posted by Tim on April 29, 2000 at 12:02:46:
In Reply to: manifold vacuum problems posted by m clark on April 29, 2000 at 00:09:42:
The other advice that you have been given is pointing you in the right direction. Check the Carb Base Plate Gasket, check along the intake manifold on both sides and check the vacuum lines.
If you have Power Brakes you will need to make sure that the Power Booster IS NOT leaking at the back of the booster. Most times you will hear a hissing sound in the cab, sometimes more evident when applying the brakes. If you DO NOT have power brakes and still hear a hissing sound in the cab then run like hell because there is probably a snake in your truck! Inspect the Check Valve on the booster where the vacuum line attaches. Sometimes this plastic part cracks or even falls apart. Look on the Firewall and make sure that if there are vacuum ports attached, that none of the lines and or rubber caps have come off.