hi can anyone help.i changed engines from my old sportrak jeep into another one,ran fine for a bit then just died.soon found out it was the fuel pump,so.changed it with the one off my old jeep.ran fine for not long and died again,same problem again,could anyone tell me what might be causing this.i will have to buy another one and put it in but dont want to if it keeps doing the same,there to expensive.please help