Can car jack go under the oil pan 1991 buick park ave?
I wouldn't do that! You may puncture, crack or dent the oil pan and have a bigger problem. Even if you use a board to spread the load around, the weight of the engine will squeeze the gaskets or deform the pan and probably cause oil leaks later. I would look for other areas to use if you must raise the engine. Typically they use a hoist to lift it. This is just my humble opinion and you might check with a good mechanic to get a better answer. Heck no, don't, use the frame rail, never the oil pan.
For model year 1989 General Motors did not produce the Buick Park Avenue. The soonest production date to 1989 was the 1991 Park Avenue. The 1991 Park Avenue was offered in 3800 engine in supercharged or naturally aspirated. The part numbers for electronic control module (ECM) or "computer" will vary based on the exact engine for model year 1991s.