Just up graded from my 2002 XKR conv to a 2013 XKR conv with 13,500 miles. Drove it home 600 miles. Today under full power a warning came up reduced power. When I first got my 2002 I'm had the same issue and had to replace one of two fuel pumps. With such low mileage I would hope that is not the case now. Any clues?

 

Was your power actually reduced? If not, did you get any other weird warnings? If so, you may have a low battery voltage issue. X150s are very persnickety when it comes to voltage. They want the battery voltage to be at least 12.5. Your vert has extremely low mileage for a four year old car. probably not used very much. I think the first thing that I would do is check out the battery at a local Pep boys, O'Reilly or the like. You may need to replace the battery.

Whether or not you replace the battery, you should invest less than $100 in a battery maintainer, most guys on the forum use a Ctek, and keep your XK plugged in when not in use unless it is going to be your daily driver.

Finally, welcome to the X150 forum and post some pics.

 

I will check that but at 90 the motor just shut down like a speed limiter. Then I went to a limp mode.

 

Doesn't sound like a battery issue to me. do you have and OBD reader module and a smartphone? If you do, plug the reader in under the dash to the left of the steering wheel. You can download an app called Torque and install it in the smartphone. You may be able to get a fault code off of your phone. If you don't have the reader you can go to an auto parts retailer who may be able to give you a reading. Otherwise you will need to go to a dealer or and indie repair shop for diagnosis and repair. Good luck!

 

In checking the records for the car I saw at 4088 miles the former owner while in for service complained that ( while on the open road at 90 mph vehicle seems to be gasping for air.) Tech responded could not duplicate due to heavy traffic and unable to reach 90 mph. So vehicle has had this problem since new.
Any ideas?

 

That description sounds more like a fuel starvation problem. Filter? Pump? Pinched line?

 

I would ignore the original owner's complaint.
You have something far more concrete and detectable.
A reduced power warning.

Infrequently driven cars like this one, suffer from varnish buildup. While cars have evolved, laws of physics with hydrocarbons have not. In fact they have got worse for newer cars with smaller ports and more things running on oil, such as the cams.

I have posted before, Jaguar has a patent and unique approach to the oil driven cam phaser. It has a locking pin that keeps oil in. So a very small amount of hot oil is being held in one of the hottest part of a non-running engine. Effectively baking- think seasoning a cast iron pan. What its banking on is an extended run when enough detergents in oil flow through and clean it out- This would not happen in a car that makes mostly short trips. Because the baking cycle is longer than the cleaning cycle.

Incorrect or regular oil would also expedite this process.

Just something else to consider.

 

I'm not real familiar with how the 5.0's ECU logic works but to me if you are getting a reduced power message, then the ECU knows something is wrong, is reducing power and letting you know what it's doing (by the indication), not just indicating that the power plant isn't performing at full potential (by the indication). Clear as mud?

 

Yes, you gotta get the codes. My '04 did the same trick, running fine then throwing out the anchor with the reduced performance warning. Turned out number 2 coil was heat soaking and opening up intermittently. My code reader pointed right to it.

 

You need to see what codes are set. If the check engine light is not on you will not have a P code and will need a reader that will read error codes from all the control units. I know the ABS and transmission controllers can cause the car to go into limp mode without setting P type OBD errors that can be read by simple readers. SDD or similar reader will read all the controllers and report any errors found.

 

Did you really get a warning saying "reduced power," or was it the yellow triangle with "Restricted Performance?" That will limit the cars performance to protect the engine. It can be for a number of reasons from Mass Air Flow to many others. You need the codes.

 

Yes it was the triangle with restricted power warning. It flashed and I forgot.

 

Going to get it checked for code today.

 

Good luck, it can be challenging understanding what the car wants.

 

Today I had the codes read there was 25 codes a lot had to do with low voltage. Replaced the battery ( original) and had the brake fluid changed.
Did not get a place to try it out at full power. Now after new battery when the top it put up the pass window will not go up. It did prior to replacing the battery.
Any help?

 

The window won't go up At All? Or, does it not go up as in AUTO up? If you hold the switch does it work? Since the battery was disconnected, you'd need to do a "window reset" for both the windows to operate correctly as well as the Convertible Top.
Hold the switch to either UP or DOWN until five seconds AFTER the window completed the travel, then do the same for the other direction, five seconds past full travel. Maybe even, to be safe, do the first direction again. This procedure resets the Full Up and Full Down settings for the window-drop upon the door opening.

 

Thanks I remembered something about that. Will try that today and let you know.