XF very, very rough Idle then dies

Hi all,
I do hope somebody can help me, I’ve tried all of the UK forums but it still has people stumped.

My one owner 2011, 3.0 Premium Luxury has developed a very rough idle on first start up then dies after about two seconds, if I press the accelerator nothing happens. I’ve pulled the codes but nothing relates to this issue and I.ve checked the start up pressure which is 40.000 KPA. I’ve replaced the fuel filter and check the lift pum in the tank which is giving a resistance of 3.1 on my multimeter and I can feel the pump energising when the ignition is switched on.

Has anybody had a similaer experience or is there anybody out there with an idea of where I need to go next? My local indy doesn’t want to touch it so I really have to sort it myself as I’m not paying main dealer prices until it’s the last resort.

Thanks
Alan.

Hi Alan and welcome to the forum.
First off we probably need a little more information, I am assuming from your ‘lift pump’ that the car is diesel?

Apologies Robin,

Yes it is, this afternoon I’ve carried out a pressure test and I’m getting 7,687,0001 at start up which equates to around 52-53000 KPA. wth the ignition on prior to cranking over I have 4,226,20873 which is approximately 29000 KPA fuel rail pressure. HPFP failure perhaps?

Alan.

Hi Alan, no probs, unfortunately I have no experience with the XF diesel but that sounds like the next possible culprit. With the diesel you take out one variable over the petrol which is spark. So you need fuel and compression and the correct injection timing.

You might try to inspect and clean the throttle body. The air intake could be jammed. Otherwise you have done all the obvious things I could think of. I just got an XF and I am taking it to the dealer for the first time for an oil change and I don’t like dealers either but I have to give them one chance.
P.

Hi Carsoncitysmith,

Thanks for your reply, that’s something I hadn’t given a thought to but it’s certainly worth investigating. The car’s only done 71000 from new but with supermarket grade diesel I guess anything is possible. I’ll get back to you once I’ve inspected it.

Alan.