Fault code P1582 - stalling

[new2jags]

Car's been in ‘winter storage’ since October but regularly started. Took it out yesterday for a run and after around 40 miles suddenly intermittently lost power. It was for all the world as if it was a fuel starvation problem (just put 70 litres in!). No fault info. displayed. On the return journey, same fault occurred, but more frequently, and 'restricted performance' warning momentarily flashed on a couple of times. Vehicle then stalled completely and I thought it time to call out RAC guy. He discovered fault codes P0603 (ECM failure?) and P1260 (security input malfunction) both of which he was able to clear. Whilst laid up, battery did go flat a couple of times, so perhaps this was the reason for these codes. A further code found was P1582, against which Mr RAC recorded, ‘electronic throttle (malfunction?) data available’. He advised against continuing my journey so I accepted a ride home on the back of his truck. Subsequent research on ’flight recorder’ code P1582 revealed it was possibly caused by the vehicle stalling and is more or less an information code, which can only be cleared by a main dealer. My problem is the 'fuel starvation' symptoms. Very little fuel was in the tank when the car was laid up, and although it didn't run dry, I did have to top it up with a gallon once or twice. A fuel filter issue perhaps, but having filled up at start of journey and driven 40 odd miles trouble-free, would any muck in the tank cause this problem? Took it for a short run today and after about 4 miles, power failure again began to develop. No fault info. displayed.
As ever, any pointers would be much appreciated.
Thanks, Leighton.

[oyster]

Hi.

Code 1582 is related to the inertia switch. To give some more information, we need model year as the codes may different from year to year.

[mike020150]

Before getting deep into code diagnostics, it is essential that the battery is confirmed as being in good healthy condition. All of the codes listed could appear as spurious recordings due to a dodgy battery. An XK8 battery has to be in first class condition to avoid creating spurious issues. If there is any doubt about it whatsoever, replace it before chasing any apparent code information, clear the codes and start the diagnosis afresh. Mike.

[new2jags]

Thank you both. The car is a 53 plate, 4.2 XK8, first Reg. Feb.2004. It's done 41500 miles. If it was an inertia switch problem, surely the vehicle would not start?
The battery was replaced September 2014 and currently shows a reading of 12.6 - 12.8v. Having no power in my garage, I trickle charge it with a 4.8w solar panel charger. During very cold weather, I disconnect and use a mains CTEK charger at home to maintain.....Leighton

[oyster]

Hi again.

As you can see from the attachment it can be five different things. A battery disconnect could help if you are lucky.

Fuel pump failure is fairly common in cars being stored for some time. You may be able to hear your pump running a few seconds when turning on the ignition.

The fuel pump relay may be jumped to pinpoint a failed relay or pump.

[new2jags]

Problem sorted - dirty/blocked fuel filters! Replaced in-line filter located under rear nearside wheel arch, which was relatively easy. Second filter located on base of fuel pump module within the fuel tank - a lot more difficult! (A very informative video is here: www.youtube.com/watch?v=hOXzt_GUY4Y) This filter, which is basically a shaped piece of mesh and detaches from the base of the module, is not a serviceable part without replacing the actual pump - going on £400! Thoroughly cleaned this 'primary filter' and took the gamble of not replacing the pump. After 30+ miles the car is running perfectly - so far! Haven't yet checked if the P1582 code has cleared.
I guess this post may be of more help under a 'fuel topic', but I don't know how to transfer it! Many thanks for the posted replies and Ian of XJK Ltd. Special massive thanks to Mr. David Marks for his help and advice....Leighton.