You should have the codes read to see whats wrong.
Depends on the engine the Park Avenue had in it.
show a diagram of a buick park avenue crankshaft sensor
To retrieve diagnostic trouble codes (DTCs) on a 1991 Park Avenue, you can use an OBD-I diagnostic tool or a paperclip to short the diagnostic connector. The connector is usually located near the driver's side, under the dash. By bridging the appropriate terminals (often A and B), the check engine light will flash, indicating the codes. Count the flashes to determine the specific trouble codes based on the service manual.
If the check engine light is on then have it scanned for codes. I could guess you into bankruptsy. It is cheaper to have it scanned and repaired.
carburetor
The size of the engine in a Buick Park Avenue from the year 2000 is a 3.8 litre V6 engine. It is the same in both the "base" model and the "ultra" Model.
engine cover
If they are the exact same engine (3800 tuned port injection) then yes.
On the back side of the engine
3.8 litre
3.8 liter