Hi,
I was expecting a 2003 XK8 to be on it's way to me today, however the seller encountered a problem with the vehicle last night and was kind and honest enough to describe it to me:

He drove the car, parked it, and upon startup noticed an amber light was displayed with no error message. He said the car drove and idled normally, and other than the light he was unable to notice any problem with the car. He took it to his Jaguar dealership this morning, and they told him the computer was returning code PO191, which he was told indicated a problem with the fuel rail assembly leaking, and was given an estimate of $1800 to repair.

The problem has not occurred since the dealership reset the amber light, so he's agreed to keep the car over the weekend and see if it reappears.

Does anyone here have any knowledge of this error code or the described problem?

I am unfamiliar with this vehicle or Jaguar motors in general, however having worked on a handful of other fuel injected motors, there seemed to be little which could go wrong with the fuel rail assemblies that I'm familiar with; either an injector goes bad, the rail itself deteriorates, or an o-ring needs replacing, with the typical problem being a bad o-ring, which is usually a quick and inexpensive repair.

My first impression is that the dealership is being very cautious about a problem which they are unable to narrow down further via diagnostic codes, and would therefore prefer to replace the entire assembly as a unit rather than hunt and peck at possible faulty subcomponents; or is it not possible to replace individual componenets of the assembly?

 

First off congratulations on finding an honest seller!

In 2003 electronic fuel pressure monitoring was added to the XK. P0191 is a fuel pressure fault. It can be as simple as a clogged fuel filter or an o-ring, or as difficult as a fuel pump requiring tank removal. Or it could be the sensor itself. See the chart below:

 

Thanks WhiteXKR, that is exactly the type of info I was looking for.