Just picked up a 2001 XK8 with 34.9K miles on Fiday, and Sunday evening driving on the highway doing about 75 mph, I got an error message saying "reduced Performance" and the engine light came on. I slowed down to 55 mph and brought it home. I searched the Forum here and didn't see any info. Car is running great and I do not feel any reduced performance at all.
Any ideas? I'm thinking that the car has been sitting for a while and was not used to being exercised and that I just need the error reset.

 

You are going to need to pull codes as a Restricted Performance can come from a bunch of different things. I have been chasing a very intermittent one myself due to something in the fuel system. When the car goes into Restricted Performance, it limits the engine to 3000 RPM.

 

Add a bottle of "sea foam" fuel treatment to the tank..and it will go away. The injectors are very sensitive to any fuel contamination. I had the same issue and this cured it. I do this regularly (3x per year) and this hasn't happened again.

 

Checking the codes is going to be worthwhile, better than just crossing your fingers.

 

Sometimes these cars throw codes...Because they want to!!!

 

Had it checked out and dude says the code told him it was running lean on one side. But since it is running great and no performance issues, chalked it up to gas.
So Eric, looks like "sea foam" is in my future.
thanks guys

 

This sounds like a one off fuel issue easily fixed that isn't going to cause you too much grief.

For any future issues triggering a warning message or illuminating the MIL, if you don't have a Code Reader or Scan Tool and need to get someone to read codes for you, always ask for the actual code(s) rather than their interpretation of them. Posting the code on the forum will then get you the precise list of possible causes and make fixing a whole lot easier.

Graham

 

Thanks Graham, good point to get the actual codes.
Where can one find one of those readers?

 

Check this thread:

https://www.jaguarforums.com/forum/g...-%2A%2A-33347/

There's a huge variety available from simple tools that read codes, through those that read and clear codes right up to ScanTools like AutoEnginuity which approach dealer facility level.

Graham

 

My restricted performance was broken tensioners last week. Misfiring, jumped timing. Only 63k miles, 2001my

 

I am trying out a neat code reader on my phone. Downloaded Torque and bought a BAXF plug in, bluetooth code reader. Lots of features and able to check codes as they pop up.