when i drive at slow speeds(10-20) for 10-20 minutes. it begins to run very rough then it stalls. it seems that if i put it in park for a minute then it will run ok. but if i push on the gas and try to drive it takes it 1/4 mile before i can get it to go more than 15 miles an hour. if the gas is pushed hard it makes it worse.almost seems as if it is flooding. air filter ok. any suggestions? would appreciate any help that you can give me. thanks

That sounds like a problem with either the fuel pump or injectors to me. Both of those are problems I would take to a technician.