Hard to start

My 2000 Crown VIctoria is in the shop because I am having problems starting. The fuel punp has been replace but after a few days I am back to the same problem. It seems that the gas is not staying up in the line.

The fuel pressure on your car is not tested in the same way that older model vehicles were tested. Testing using those old criterion leads to erroneous results, and erroneous parts changing. Your Vic has a Fuel Rail Pressure & Temperature Sensor (FRPT) which sends signals to the engine computer. The engine computer adjusts the amount and time that the fuel injectors spray based on this information. The engine computer MAY, also, use this sensor information to adjust fuel pressure (fuel pump run-time). The repair data, such as alldata.com, will have the instructions, and information on this point.

FYI: http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?chapterTitle=Components+%26amp%3B+Systems&partName=Exhaust+Gas+Recirculation++EGR++System&pageId=0900c152801e7bf8&subChapterTitle=Fuel+Rail+Pressure+%26amp%3B+Temperature++Frpt++Sensor&partId=0900c152801e7bda