Land Rover Repair: Idle on a 1999 Land Rover Discovery, land rover discovery, throttle position sensor

Question
QUESTION: I have a 1999 Land Rover Discovery with a 4.0L.  When you start it the idle stays at about 2K, It will go down to 1K after driving.  Of course which still to high I have replaced both the Throttle Position Sensor and Idle Air Control Valve.  In suggestions on where to look next?  Is there a actual idle set screw. Its been a long time since I worked on cars. I can not afford to pay somebody right now.

ANSWER: There is not idle set screw.  It should run at about 1500 and then drop to 750 after about a minute.  I would suggest having the ECU adaptations reset by someone with a factory compatible scan tool.  You could also try to get a software update for the ECU.

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QUESTION: Thanks will I have to go through a LR shop to get a software update for the ECU?  I had a mechanic hook it up to a scanner, when it was missing.  Should it be throwing an codes? Thanks again for the help.

Answer
You will have to go to a shop with a Land Rover factory compatible scan tool, which would be a dealer or independent specialized Land Rover shop.  

You did not mention anything about a misfire before.  If there is a misfire there would be codes.  If you are just talking about a rough idle, there would not be codes.