2001 jaguar XJR. Just hit 160k did all preventive maintenance but now I am getting restricted performance at first start up. Oddly enough it goes away at highway speeds then comes back up when slowing down.

Should clarify that it does have a check engine light and gives me knock sensor codes. Ideas?

 

A faulty knock sensor will give you a restricted performance condition.

I see a knock sensor replacement in your future.

 

Replace knock sensor?????

bob

 

I figured I would regardless. Just seemed odd that it would go away but come back only when coming to a stop.

 

There are two types of knock sensor depending on the year of your vehicle.

You should fill in details of your location, model and year of your vehicle, in order to better participate on the forum.

 

If the car doesn't rev above 3k rpm probably its knock sensor.