Just a thought:

My 2002 Daimler model is fitted with an immobilizer system. I guess the 1998 models also are. If so the difficulties in starting the engine could result from occasional inability to deactivate the immobilizer properly.

 

I have already thought about this.

I want the engine to crank every time. Someone tell how to permanently deactivate the blasted immobilizer.

 

Good Morning! This is my first post as I just joined yesterday, and just picked up my "new" 1996 XJ6 the day before that! I drove it around all day yesterday, and low & behold, I went out last night to run to the store and ... wouldn't start! As stated above in another post, all the bells & whistles light up but no crank at all! Have dreamed all my life of owning a Jag and I know they can be a costly item to have so I'm glad I've joined this forum for advice!
Keeping my fingers crossed that it starts when I leave for work today!

 

Welcome! Try waiting until everything has "booted up".

Seems like if I wait a couple of secs., it fires up. Also, find all the fuses and make sure everything is pushed in properly. This seemed to help when I did this recently.

I also tried changing keys(if this applies) and also seemed to make a difference.

I hope this helps and I hope that you have a great experience with your Jag.

 

If you look at my post #16 you will a great deal of information that is related to the no start situations. In the second to the last paragraph I posted information related to the Exciter Ring and this is the comment

“If all attempts have failed you may want to look into the exciter ring located at the ignition lock. This ring receives a signal from your key that enables the starting process. This part of the no start process in not a common occurrence but should not be overlooked.”

This ring is not pricy and from what I understand not difficult to change. However, do not overlook the possibility of a bad relay and if you haven’t already I would suggest swapping out relays and see if the problem moves to another location.

For my own curiosity is it that the car intermittently turns over or is it that it turns over and intermittently starts? I want to be sure I am understanding the situation.

 

Gives me error messages "stability control fail" and "traction control fail" after system check! any ideas?

 

Welcome to the forum gsweeny.When you have time please visit the new member area and introduce yourself.

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

We need more information. The year and model of the car for starters. The error messages indicate a problem with the abs module, which not not keep the car from starting. There may be codes stored and you need to read those codes. Buy an inexpensive code reader, you will need it if you own a jag.
There are so many reasons for the car not to start that it's hard to know where to begin without more information. One thing you can do is to remove the battery and have it tested by autozone, advance auto, or others.