FUEL SYSTEM PROBLEM

My 2000 galant started with the lower radiator hose leaking water which somehow lead for the car to not turn on. I repalced the hose and somehow the car didn't want to stay on on its own. The only way to keep pushing on the gas petal. When the car heats up then the car stays on its own but its marking lower than one. I changed the fuel pump and strainer, gave it a whole new tune up( changed spark plugs, and gave it a oil change) the car starting shaking in the front so I had to change the plugs that go with the spark plugs. The car worked great for a day then the car went back to the same problem. ( Marking lower than 1 and cant stay on on its own. I NEED HELP!