julianfoulger

Try this...
See https://landroverforums.com/forum/discovery-i-39/base-idle-speed-setting-96-disco-95426/. Follow these instructions (but get the engine oil to 85 degrees + - ignore instruction 1.) which takes the reset back to basics. i.e. It is ensuring that only air through the butterfly valve is getting through (use clean rags to blank off the hose from plenum to IACV - there is obviously a special Land Rover hose for this back-to-basics reset [instruction 4]). Reconnect everything, restart the engine and then slowly adjust the idle valve in small steps, leaving 2 mins between each turn until you are at 26 steps/steady idle at 870 rpm or so.