I have a 1987 Lincoln 5.0 Town Car that has a vacuum leak sound coming from under the dash, but when in drive it goes away as I accelerates. What is causing the problem.
Hello Eddie –
If you have a vacuum leak sound coming from under the dash I would agree that you must have a vacuum leak. The sound diminishes when you accelerate because engine supplied vacuum drops during acceleration. To find out what is causing the leak, someone with a good ear needs to look and listen under the dash for a vacuum hose disconnect or a leaking vacuum component etc. It should be easy to locate.