My guess would be valve seals in the engine. The earlier year 4.6 L V8 was problematic for early failure of valve seals. If it smokes worse after idleing, and then clears up somewhat that should be your problem. I would guess somewhere between $400 - $800 for repair. Low end at a independent mechanic, high end for a dealership.
my 1985 ford crown Victoria ignition has locked up! what do i do?
go to the mecanics
check out strutmasters.com they have what you need.
Buy a new housing....not that expensive
Look for a leaking hose, water pump, or raditor find the leak and fix it.
Replace it
it depends on who you buy them from and if thier used or not
Start with a complete tune up including spark plug wires.
Pick up a tub of "Dr. Tranny Shudder Fix" it does work, and as it says on the package "instantly". I paid $6.99
there is something wrong with your switch in the door you may have to change it
Put a new master cylinder on. Throw the old one away.
All you need to do is replace it. It would take a welder to fix it.