1999 VW Jetta having issues starting

I have the same car just 2003 model. Why would you POSSIBLY change the fuel pump which is one of LAST resorts to solving this issue!!? Sure the back seats pop up and the pump is right there, it's simple, but GOSH what a pain in butt. And the problem is still there?? hmm. Secondly, what does the coolant temp sensor got to do with the start /idle with the car?? If you are in severe cold weather it does take a moment of 2 for the pump to get the gas to the injectors. That gas line is cold and you want that gas to be just jump up and be ready to go?? not happening. You wouldn't get out of bed and throw on your jog outfit and start sprinting down the street, do you?? Same effect. The body isn't toned up for that event. Car's have the same attitude.. gotta warm up