My car will start fine but will die right off. Have to keep foot on the gas to keep it running

Yes. This started after I had a guy at O'Reilly's check the battery. Then when it died at a light on a really cold morning, I killed the battery, so had to replace. They could not get it to run, so they reprogrammed computer. I had a code for oxygen sensor going bad, replaced them. Got tune-up, new plugs, wires, fuel system cleaning (injectors, etc.) also had a gasket leak. Two weeks later, I drove it it 2 blocks, shut it off, got back in, drove it 2 blocks and it died as I was pulling into parking place. Got it over to garage by keeping foot on the accelerator, it died pulling into space. Within 10 minutes, mechanic went out to check it, it started fine, idled fine, is still doing fine.