So decided to my old lady and the missus for a run to Cornwall for a few days in Bude.
Had a nice time in a quirky, in a good way surfers hotel right on the beach.

Left at 10 am on Friday 5 hrs later, should have been a 4 1/2 hour journey all in, was just getting off M5 onto M4 bonkers traffic all the way and due to traffic on south side of M25 decided to go clockwise to north: ave speed for the day 30mph traffic was horrendous and just when I thought it couldn't get any worse!!

The XK8 decided to spit the dummy out! Restricted performance and felt like no connection from throttle pedal to throttle body. I was in the 3rd lane just past Potters Bar, where they stole the hard shoulder to make a new lane, and just managed to get across the lanes with Hazards on before she conked out, in 4 solid lanes of traffic at 6.30pm.
Left it a few minutes and tried to restart but nothing going.

Phoned breakdown company and police. police arrived first then breakdown truck about 30-40 mins after car broke down. breakdown guy looks for tow hook on front of car and then turns ignition key and the bugger starts first click he drives it onto his platform and we go home in back of cab. It also drove off the platform at home?

Went out this morning and no codes are there, had a look at MAF which seems to be a new one -DMA 0113, so with nothing to loose did a hard reset and took it for a spin and it runs really well.

I will hook up TORQUE PRO for a while and see if anything comes up but I am stumped.
Policemen were brilliant and very helpful. only saying as they get a lot of bad press.

 

Have you still got the original throttle body ?

Early cars did have problems and many were replaced under warranty. You can tell by looking at the throttle body - if there's a little sticker with an "eye" on it, you have the later one. If not, it would be worth carefully cleaning around the area where the butterfly closes against the "tube" of the throttle body. There's basically no direct connection between cable and butterfly and the butterfly can stick under certain conditions and fail to open. The usual symptom is engine shut-down on the over-run which isn't what you had, but for pretty much zero cost, it might be worth having a look.
If you have the later throttle body (with the sticker) - Jaguar don't recommend cleaning as it is coated with a special material which could be compromised.



See also here :

http://www.jagrepair.com/images/TSB/...ion%20S514.pdf

(Thanks again to Gus Glikas)

 

Hi Devon, mine is the update 2003 model so no TB issues that I am aware of. Did think it may be crank or similar sensor as it worked after possibly cooling down.
The only other possible connection is that all day fine but the issue came after headlights were on at night?

 

thank you David very interesting bulletin, do you suppose that all units manufactured after 98 have the upgraded throttle body unit? I have not yet checked mine.
Joesoap, sorry to hear off your misadventure I've been to Cornwell beautiful location,
hope she behaves better on your next trip.

 

Joesoap - sorry - didn't read your "signature" carefully enough - just saw '1997 XK8 !!

jeremys - Getting to the limit of my knowledge, but I think it was in late 1999 that the system was completely changed - AJ26 to AJ27 engine. This problem is only relevant to the earlier engine as far as I know, although later (AJ27) can also have throttle body problems. I think I am correct in saying that if you have the cylindrical vacuum actuator for cruise control on top of the throttle body, you have the earlier AJ26 engine.

 

Joesoap, check your alternator. Could be a low char, gradually depleting battery. Add a corroded battery connector and intermittent high current draw like headlights, it could make the electronics go unreliable. Happened to me once, slow battery drain, then you hit that low voltage point. Hope you track this down.

John

 

Will do Johnken, although dash voltmeter always shows 13v or is that 13.5 at 12 O clock.
My gut is still on a cam or crank sensor or something getting hot and working when cool again, but still hunting for answer to get a solution.

 

Fyi when this happened to me, I noticed a slight intermittent movement of the volt gauge indicator at idle. Good luck with it.

John