Land Rover Repair: high revving, throttle position sensor, air control valve

Question
I have a 1997 Discovery 1 V8i that revs to around 1500-2000 rpm after it has been for a run and restarted. After the restart the revs die down to 750 rpm after a few seconds. It seems to run perfectly well at all other times. On initial start from cold it does not have this problem, only when it is hot. I have a complete vehicle for spares and have swapped the mass air valve and the screw in valve mounted on the rear of the plenum chamber with no change. I was going to swap the throttle position sensor but the plugs are different - mine if square and the spare is round. Can you offer any assistance or help. Regards.
Eddy.

Answer
Hi Eddy,

try swapping out the idle air control valve (IACV) also known as the stepper motor.  When this fails you'll see low or high idle speed, poor idle, engine stalls or difficult starts.  As for the TPS, I'd only swap in one that matches your engine. I don't think I'd want to modify the connection harness just to see if it resolved your problem.

Best of luck,

JohnMc