Normally I know enough about car repair to just be dangerous (unless for MG Midgets). However, after reading this thread I was able to have an intelligent conversation with the repair shop that replaced a failed Bosch fuel pump and filter in my 2006 XF roadster 7 months ago. Recently my '06 started cranking for a long time before start, and sometimes it took a second cranking. It would run rough for a couple seconds then smooth out. Told the repair shop it sounded like the fuel rail was losing pressure after the engine shut off and the check valve in the new (7 month old) pump might be the culprit. They tested the pressure and found that after engine shut down the pressure went from 60 to 15 immediately. They confirmed the fuel pump was bad. The replacement pump they had put in was a Delphi FE0346 which is supposed to be even better than the original Bosch 66150. They are replacing it now under warranty. Felt good to know what I was talking about with them and they seemed impressed that I did. When I was telling them what I thought the problem was they were all nodding their head in agreement. First time that's happened. Anyway, thank you for the info and for allowing me to be more knowledgeable than just dangerous. Score one (of many) for the Forum.