You mention you have to prime the engine to make it start? Do you mean starting fluid? The issue you are having is very common and is usually associated with injector ball seat leakage. After time the seat will wear or corrode causing excessive injector return flow. With too much return flow the CP3 can not produce enough fuel pressure at cranking speed to make the injectors fire. Once the engine is running and up to temp the expansion of the injector components will allow the ball to seat enough for it restart, In recent years, Bosch has changed to a stainless body injector design to combat this issue. With the proper tools, you may be able to isolate the problem to 1 or 2 injectors. But since all of the injectors have been subject to the same fuel quality and run time, be prepared to replace them all eventually.