No, they are not the same. The body style changed in 1992.
Yes, they are identical
For a 1991 Ford Crown Victoria : " regular " unleaded , 87 octane
Take the door panel off,you will need to remove 3 bolts for the window motor and then 3bolts(maybe4) that hold the regulator to the window
In the gas tank.
4
Yes, both model years are AOD transmissions.
take the door panel off and unbolt the regulator and jam the window until you can replace the regulator
According to my Chilton's book : For a 1991 Ford Crown Victoria ( 5.0 / 302 and 5.8 / 351 ) With engine oil filter change ( 5.0 U.S. quarts )
10 degrees advance
Often in the owners manual is where i found the one for my 1991 Crown vic. Hope you have your manual?
The best is to buy a new one.
On a 1991 Ford Crown Victoria : Using a funnel , you add automatic transmission fluid through the ATF fluid level dipstick ( in the engine compartment , near the firewall , on the passenger side of the engine )