Hi there,

This is my first post.

The other day I bought a jaguar xj6, 4.0 sovereign lwb for £500. It was a bit grubby but now it is all cleaned up. I drove it back from Liverpool to somerset with no problems. However on this journey I did think I was lacking in power and it didn't want to rev above 2500rpm. When it reached top gear it would then rev over that. Now today I went to start it and the battery was completely flat. I jump started it and drive off and it went like a rocket. Sport mode worked and so did the lockdown which didn't before.
I drive it for 15mins which entailed booting it a lot and scaring myself! I then got back home, left the engine running, got my dad and showed him that it had magically fixed itself. Whilst showing him I switched it into sport mode and it went back to only revving below 2500rpm.
Now, my question is: Is it in "limp home mode"? And what would/could be potentially causing this? There are no warning lights on the dash. Is it likely to be immenint gearbox failure or an electrical fault or something else?

Then next problem is that the inside of the tyres are warn bald on the front whereas the centre and outer parts have 5+mm of tread. Is this just a case of the tracking being majorly out?

Lastly, when I switch it on it idles smoothly at 800 or so rpm, however when I rev it a bit (it will rev all the way around the counter) it returns to a high idle (around 1500rpm)

Thanks

Tom

 

If the battery is old that can cause all sorts of issues, as like all cars now days they rely on the computers to send the right signals.

I personally would buy a new battery and start from there.

Also if you got a code reader plug it in read and clear any codes that show up.

 

I agree fully with the "bad battery" diagnosis. Even a battery that "seems" good can cause all sorts of grief. When driving, the voltage gague, on the dash, left hand side, should be reading about 14 volts. Get the wheels tracked and balanced to eliminate the uneven tyre wear, for future reference, that is.

The high idle is a common issue and has a variety of causes, from sticky idle control valve / weak throttle return spring / gummed up throttle body and then some. Lots of posts here in the archives, just do a search "high idle".

Enjoy the car, I do! And welcome!

 

Welcome to the forum. When you have time, please visit the new member area via the link below and introduce yourself.

New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum

 

I bought my X300 4litre last November - it was great for a few days! Then I had warning lights on for engine problems, transmission problems and finally - no start! I charged the battery, which was tiny and all the symptoms went away - for a few days - and then they began again! Bought a new, much bigger battery. All has been fine since. I wish I had bought an even bigger battery!

 

As far as the tire wear goes that is normal for the inside to wear more than the outside both front and rear on the X300. The wheels are set up to tilt in at the top slightly. The only way to counter this is to have the tires flipped on the rims. Even my XK8 is set up that way on the front. The back seems not to be tilted.