1995 Other Oldsmobile Models Olds 88 3.8L

I just purchased this car cheap. It needed brake work but otherwise seemed to run fine. I changed the air filter and plugs. I noticed a miss or hesitation upon acceleration otherwise it was fine. Then it spit and sputtered on the highway a couple of times and returned to normal. But the last time I drove it it died on the highway, just lost all power and finally stalled. I could not get it to restart but my brother in law happened by he unplugged the air flow sensor pushed the pedal to the floor and it started right up then plugged the sensor back in. I got it home(I won't drive it into town) it starts fine I rev it up and its ok but if I hold the gas about halfway it revs dies down revs back up and so. No lights came on or come when these things happen.