94 Lumina starts-but stalls out

I'm a middle aged single mom who just went back to college after my children left home. And, after two years with no vehicle, in January I purchased a 94 3.1 Lumina from an acquaintance of my son and daughter-in-law who happens to be a mechanic at a used car dealership. Despite the 127,000 miles on her, the car's exterior is exceptionally clean. But, that doesn't count when it's not running right?
He allowed me to take the car for one week before the final purchase to see if I really wanted the car and I agreed. Three days in, I experienced what he intitially told me was "I had run out of gas," despite the fact the guage read almost a quarter of a tank. Previously, I've never let that happen-it's a no brainer. I was out with my daughter and the car stalled while driving at a slow speed of about 15. The car started up immediately, but I noticed the idle was slow and kind of rough. When I put my foot on the gas peddle she would hardly move forward, except in a delayed action knid of way. After a mile of taking my foot on and off the gas peddle, she finally stalled for the last time and wouldn't restart. I noticed a gas smell and the battery was just about run down, so, my daughter and I decided to pushed the car off the main road and to call my son. When my son and the man who I was purchasing the car from arrived, the man looked under the hood while I waited in my son's van. When he came back he said I had run out of gas because when he pushed on (damn I can't remember?) and all that came out was air. We went to the gas station-filled it up-problem resolved, right? A month goes by after I puchased the car with no problems, runs beautifully. Then this past weekend it began all over again. But this time I immediately recognized what was happening-especially since I had almost a full take of gas. Even though we were able to make it the ten miles back home, I couldn't take her past 45 or the engine would start to vibrate all to hell. I prayed all the way home. The next day she started, but stalled as I attempted to take her out of park. She'll start-but very low idle, once again, you can't put your foot on the gas or she stalls, and I've noticed a big gas smell when she's running. Any suggestions or advice as to what my next step should be will be greatly appreciated. Thank You.

i'd say you have a fuel leak. probably from the pressure regulator. make your son fix it, sounds like he owes you one anyway

Check the Line in the tank. If it has a hole in it. It will pick up air. Ie the tank may be 3/4 full but the pick-up point(hole) is above the fuel in the tank. Had that happen on a Volvo years ago
I have an APV also. Just got it.