I have a '01 XK8 with 60k miles and have recently
(2-mos.)encountered the following recurring problems;

1. when traveling at 50 mph and quickly accelerating,
the car goes into limp mode and I get the "Restricted
Performance" message.

2. also, while driving on the highway between the
speeds of 60 to 70 mph and without any notice, either
the ASC or the TRAC "Not Available" message will
appear or the Airbag or ABS indicator lamps will come
on.

3. finally, my engine lamp comes on for about 100 to
150 miles and then goes off, unless I accelerate or
brake quickly, in which case, it will come on again.

Needless to say, I succumbed to my fears and took it
to the local dealership and after inspected, I was
told that I needed a new throttle assembly and ABS,
which BTW is going to cost 5k.

That's all well and good, if it happens to be true;
but I'm inclined to think that the problem is
electronic.

Your thoughts are greatly appreciated.

 

Sounds like you're getting the shaft. Where do you live?

Try cleaning the Throttle Body and Mass Air Flow Sensor, this usually is a miracle cure for many driveability issues. I've experienced this cure myself. BTW, Throttle Body should be replaced under warranty since there is a service campaign on it.

 

(Nassau County) Long Island, NY