Question about 1998 Ford Expedition
Yes, this sounds like your heating system may lack vacuum. The system is designed to fail in the defrost mode. Some vehicles shut down ac compressor under heavy acceleration, but you did not mention heavy throttle.
So, look for vacuum leaks, you may need to install a vacuum reservoir. You may have engine performance issues, causing low manifold vacuum, you may have a check valve that failed, so under acceleration, the vacuum is not shut off, but rather evacuated into the engine...
Posted on Oct 15, 2010
Testimonial: "Thanks a lot for you help, I found a broken Vaccum hose; just plug it back and the problem gone!....A+++++++++++"
A 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
The service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
Tips for a great answer:
Jul 11, 2011 | 1998 Ford Expedition
Dec 01, 2010 | 1998 Ford Expedition
Oct 10, 2010 | Ford Expedition Cars & Trucks
Jul 31, 2010 | 1998 Ford Expedition
Sep 09, 2009 | 1998 Ford Expedition
Jul 26, 2009 | 1998 Ford Expedition
May 22, 2008 | 2002 Ford Expedition
251 people viewed this question
Usually answered in minutes!