My 04 X350 with 70k miles began missing badly on warmup and spewing fuel onto the ground under the engine. Once warmed up problems would go away. Turned out the fuel pressure sensor had become brittle and cracked. This is a high risk condition that should be examined by all owners to avert disaster. The part is cheap and easy to replace but could destroy the vehicle of not addressed. It is a ford part used on the 2003 Lincoln Continental and some Lincoln LS and Ford escorts, Check Rock auto for interchangeable part numbers. The Jag part number is AJ87977.

The sensor is located on the front of the fuel rail near the EGR valve and is attached with two small bolts that are easy to reach. Two o rings supplied with the replacement provide sealing. The pic below shows the old unit with a hole where the vacuum nipple was. The nipple broke off when I removed the vacuum line.

 

Mine sprung a leak last week out of the clear blue sky. A tiny hairline crack formed right in the middle of the unit, nowhere near any seams.