In this article and video Ford GDI & GTDI Fuel Pressure Testing is reviewed and what to expect using a gauge verse a scan tool is shown. Each tool can display a different value. It is important to be aware of this when testing.
When servicing the crankshaft pulley or crankshaft sensor, it is important to check sensor to trigger wheel alignment. If timing is incorrect you could have a hard start, fault codes or a no start condition.