98 Disco 1 V8i SFI

So I had replaced a stepper motor 3 months ago to cure high idle and no difference. (The previous one only lasted 18 months but was perfect for that time) Having checked everything else as suggested I decided to remove it and take another look.

Well there wasn't really much in the way of crud in the hole as I had cleaned it before.

But I did notice that on one side of the conical tip of the stepper motor plunger there was a bright metal scratch mark into the black material. Also when I looked straight down the plunger the shaft is very slightly off centre. I am thinking maybe the shaft tip hasn't been seating correctly in the conical shaped recess in the throttle body and in an effort to push itself home it's deflected the shaft off center (just a little). Does this sound normal and am I just clutching at straws?

Thanks for your opinions
Alan

 

I think you are onto something with that.
Not sure how you would correct it though.

 

I wonder if there was some way you could compare it to another idle valve. If you were near me I'd let you pull mine, inspect it and give it a shot...

If your on to something here, which I think you might be, I suppose the only way to check it would be to get another idle valve or get a scanner and monitor it's output. Look for unusual output. Thats what a rover tech would do I suppose. Out of curiousity at what mileage did your idle air valve originally go out?

Is it doing the exact same thing it was doing when you had replaced it the first time?