Stalling while under load

I have a 1998 olds Achieva with the 3.1 V6. A few weeks ago my check engine light came on had the code checked and it said the number 3 cylinder misfired. On the way home the check engine light went out. The next day started car ran fine all day, wife came to get me from work and on the way home after stopping at a light the car started to chug as I acelerated from the stop, then the motor almost stalled out as I was giving it gas. Stopped checked all my conections, hoses, etc and nothing looked wrong car started right up and drove after a few min started to stall while driving. If while it starts if im driving I can put the car in neutral and turn off and restart the car then will drive fine untill I try to floor the gas or if I have to come to a stop and take off again if I turn off and restart the car it will drive fine for a few min then starts up again. Get home let the car sit over night next day starts and drives fine in the morning then starts again in evening, I took out and cleaned my MAF sensor seemed to fix it but two days later it started the same thing again. Also the car has 130k miles on it.