I have a 1.8vvc 143bhp k series in my GTM Libra it seems to have a problem as it sometimes does not idle and will sit at 2500 rpm and today it was sat at 3500rmp.
It has a 48mm ali throttle body and I have checked the inlet manifold for leaks but did not have any.
Anyone got any suggestions.

If you get no answer on this forum, try this one....http://forums.mg-rover.org/

You may need to clean and/or reset the idle valve.

i have the opposite, my k series idles from cold at about 800rpm
and untill the needle is 2/3 up the scale, it can be a real pain driving, as it stalls

(thats in my road car)

throttle position sensor?

I have cleaned the idle control valve out will see tomorrow if it has worked otherwise may need to check the throttle position sensor how do I know this is working correctly.

Check the inlet manifold is tight on the head.

Cleaning idle control valve seems to of done the trick took more than the 20 mins stated on the link more like an hour.