I have a Mark vii and the front suspension has lowered almost to the tires and doesn't come up anymore. When I start the car the air compressor does not engage so not sure what the problem could be!
Normally it is caused by the suspension losing its air pressure caused by a leak in the air ride system. I personally take it to a Firestone Store/ repair facility and if you speak to a manager of a Firestone Store Manager and explain whats happening and ask where is a air suspension store within there district then they will direct you to the correct store. I live in Mesa Arizona yet the Air Suspension specialists are in Tempe, Az. about ten miles away at the Lakeshore and Baseline store in Tempe. They will need your car for a couple days normally and they charge a flat fee of $95.00 and if its a "O" ring they only charge the $95.00 check out and fix it. Let a shop fix it if you can since these cars are much easier to work on a lift.
I had this happen on my Bill Blass a few years ago and I had a leak in the system and kept relying on the compressor to air me back up but finally I threw a rod in the compressor. Thus no more compressor noise, now the compressor has a air valve on it so if you are in a bind you can fill the shocks from that air valve and it may hold for a day or two, but I bet you either have a -O- ring or a bag leaking. I personally purchased a 1990 Lincoln Repair Manual published by FORD so I can do some of my own repairs.