Help

I have a 94 grand am se 4 cy. It ran great for the first couple of days. Well all of the sudden, it will die at about 30 miles an hour and wont start back up. I replaced the fuel filter and spark plugs. It seems no gas is getting to the engine because when I stick gas in one of the air tubes leading to the engine, it will start. But its only stayed running twice when Ive done this and now it wont start even for this. The starter is fine, thats been checked, but it putts like theres no gas in it. Any suggestions as to what the problem could be?