1990 Chrysler New Yorker engine runs rough, has stalled twi

Engine Performance problem
1990 Chrysler New Yorker 6 cyl Front Wheel Drive Automatic

my new yorker was running fine I stopped at a store to get a few things which only took a few minutes when I came back out and started it, it started running really rough. It starts fine and will run alright for about 5 minutes or so while driving then it starts running rough again, it won't pick up speed very quickly and has popping noises if I try to push the gas pedal harder, when it idles it still runs rough. It has stalled twice since it started acting up, both times while backing out frrom where my car was parked. Plus, it has a low to moderate oil leak coming from the passengerside of the engine, unknown if its related, but I cant find the exact location. Since it started running rough I've been keeping an eye on the oil level, and it is still at good levels. I've had people tell me that it could be the oxygen sensor, the mass airflow sensor, or the spark plugs and wires. I could replace them but dont want to put to much money into the engine if its going to be a lost cause. Any help would be welcome.