I’ve had my XKR for 16 months. Bought it w/ only 32k miles. It has 39k now. The TPS module glitch comes & goes, but just a few days ago. The average miles per gal is changing quickly instead of sitting at 10 mpg normally without changing around. Now, at idle, it drops .1 every 30 seconds or so. But driving, it goes right back up the same way. I notice things. I just recently lost my Aston Martin Vantage Roadster in a car accident. Trust me, I’m a car and motorcycle enthusiast. I notice anything out of the ordinary

 

When you say at idle, do you mean when stationary? If so the average mpg will drop, and the rate it drops will depend on how many miles you have done since you last reset the trip counter. The instant mpg changes rapidly - perhaps you have confused the two?

BTW you obviously didn't notice this is in the wrong forum.

 

Welcome to the forums Robert,

I've moved your question from X100 to X150 forum. This is the place to post questions about your model.

Please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some information about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

 

No instantaneous readings on these cars but "reset" is the key. If the trip meter has not been reset for a long time, the average changes very slowly as it is calculated over a very large number. Reset it and it starts over so will change visibly depending on if you are idling, cruising or blasting cobwebs from the exhausts.

 

The MPG figure that shows on the panel where the Speedo is can be changed

There are 3 options A B or Auto. Auto gives the real time MPG where as A or B gove the running total since a reset.
The option can be changed by selecting A B or auto on the central panel.

The figure shown on the speedo panel can be changed by pressing the button on the end of the lefthand stalk. range,MPG etc.