I have been reading all the articles on idle problems but none sound like my problem
my car is a 95 XJR6 feels like it has automatic idle
This afternoon reversing down the driveway no throttle at all just idle the throttle picks up speed like the choke has been switched on throw it into neutral and the idle drops back to normal
then a quick blip of the throttle it seems to stick move the shifter from neutral to park the idle comes down driving along the highway its like cruise control on its had a throttle body clean idle stepper motor clean ,hoses checked new oxy sensors water temp sensors coils fuel pressure reg fuel rail
the xjr has no egr system I just plugged in the scan tool seems everything is running right no codes car runs very smooth is very powerful
I am at a loss it has been doing this of and on for a year no one has been able to diagnose it as it doesn't do it all the time it seemed when I put it into sports mode it did not do it but I noticed this afternoon it did it in sports mode
Any answers is there a test for the stepper motor bar replacing it just got it back from the shop 3 days ago it hadn't done it for ages now it seems to be back again

 

Though the symptoms are not *exactly* the same, I've experienced similar problems. Long story cut short, adjusting the throttle cables did the trick in my case.

Can't hurt, might help, costs nothing, takes five minutes.

Someone posted an excerpt from the manual describing the procedure which I could never quite understand. I just slacken each cable and then re-tension until the engine speed just picks up...then slacken off a bit again.

Cheers
DD

 

Just noticed it only does it in normal mode not in sports mode and when I drive around for a while in sports mode and switch back to normal mode it doesn't do it for a while
Thanks Doug I had been suspecting the cable adjustments but the Indy I go to had already checked that and when he did adjust the cables as I was not getting full throttle
I will ask him again to have a look at it just spent $1400 on it last week so not motivated to spend any more on it this year overspent my budget big time this year cant be much left to replace (LOL)

 

I would check/replace the spring on the 'throttle return valve' (think it's called that!) it can go slack over time, and not preform like it should. It's pretty easy to get to on a NA car, and only a little harder on the S/c cars. I had a very similar problem with my car, and changing the spring cured it for me.
Dale.

 

delhump is correct.

Jaguar addressed this years ago.

bob gauff