Could be valve seal's, but you say lots of oil. Most likely the rings are finished, or both. Means an engine job. You most likely see a little blue smoke out the exhaust. Check to make sure all the gaskets are good, and not leaking oil. If its the valve seals, you will see just a puff of blue out the exhaust on start up only. If its the rings you will see blue all the time. Good luck.
For a 1992 Ford Crown Victoria : ( it came from the factory with 5W-30 )
5/w20 ========================================================= For a ( 1993 ) Ford Crown Victoria ( 5W-30 is the PREFERRED oil ) 2001 and newer Ford Crown Victoria Owner Guides show to use 5W-20
The 2001 and newer Ford Crown Victoria uses ( 5W-20 engine oil )
A 1993 Ford Crown Victoria came from the factory with ( 5W-30 )
5W-30 is the preferred oil according to the Owner Guide
According to one of Ford's websites : For the 4.6 liter V8 engine in a 1994 Ford Crown Victoria : ( Motorcraft FL-820 engine oil filter )
5w30 in the cold, or 10w30 in the warmer areas.
According to the 2003 Ford Crown Victoria Owner Guide : ( 5W-20 engine oil ) ( 5.7 litres / 6.0 U.S. quarts of 5W-20 with engine oil filter change )
5W-20 , according to the Owner Guide
You can use your favorite oil whichever it might be. Grade 10w30 or for colder climates in the winter 5w30 will do.
5 w 30 ( according to the owners manual )
5 w 30 , according to the Owner Guide