Look at your schrader valves. If there are no threads on the outside of them, and it's set up for a quick connect system, it's R-134a. If there are threads visible on the outside, it's an R-12 system. If the schrader valves are R-12 valves, and you're not the original owner of the car, I'd recommend you take it to a service center to have a refrigerant purity test done to determine if it still is an R-12 system, or if it's been retrofitted to R-134a.
R-134a a completely empty system will hold 28oz
all firebirds 94 and up take 134a freon
134-A
I had a 94 & 96 taurus and you had to take the ash tray out to get to it.
94 Taurus never had a 3.3L engine, only 3.0L and 3.8L
the vehicle takes R-134a for the type, and the system holds 1.5lbs
Ratchet and flat screwdriver
The diagnostic port on a 94 Ford Taurus is located under the hood near the firewall usually on the driver's side. Ford started producing the Taurus in 1985.
R12 if Factory and if someone retro-fitted it, there should be a sticker signifying the charge with R134. Best to take it to a shop with an ID capable machine (they'll bill you for the labor)
R134a.
Take off glovebox, undo computer by taking plugs out, pull out, take old freon out and put new in.
The original freon is R-12. Good luck finding it and if you do expect to pay over $ 100 per pound. The system should be converted over to 134A by a mechanic.