I start my 98 Disco today and the RPM gauge went all the way to 3k, it then went away after a while. This also happened a few days ago in Neutral, just not as high, however, it goes away, Whats the problem?

 

Does it only do it when the engine is cold or can it happen when the engine is warm too?

 

not really sure since it just stated happening, however a few days ago I noticed that when I went from D to R and passed through N, the RPM when up at N, just not that high, like 1500 rpm and the engine was warm.

 

Clean youir throttle body and stepper motor.
Your coolant leak worries me, that might be having a effect on it as well.

 

the coolant leak is NOT new, its an external small head gasket leak with a few drops every once in a while. However, this idle issue is new. It seems like it happens when its cold when I start it and it hasnt been running for a few hours. After I drive it, you can still feel it a little in DRIVE and REVERSE that idle is just a bit too high but it goes away completely after a few minutes and then idles fine, like after a drive, it will idle fine in PARKING and NEUTRAL. Could it be the MAF sensor? What and where is the stepper motor?

 

The stepper motor is also the Idle Air Control. You need to download a RAVE manual. Google it- it is free. You need to clean your throttle body, and might as well do a seafoam induction cleaning. If you search, there are lots of posts about it. I think Spike even has pictures of the throttle body cleaning.

 

After you do that, if the high idle is still there, start looking for a vacuum leak. Once fixed, go do your head gaskets before you toast your engine.

 

someone mentioned the stepper motor and i read on here somewhere that the stepper motor is the same as some early 90s chevys, is that true? I can just replace that first, thoughts?

 

A stepper motor from a 1997 Jeep Cherokee with the 4.0 engine will fit and is about $45 at AutoZone.
But if the port that it seats into is dirty then a new one will do you no good.
So make sure that you also clean the throttle body and port that the stepper motor goes into.
The stepper motor is closest to the t-body opening on the front of the t-body.
DO NOT MESS WITH THE THROTTLE POSITION SENSOR!! That is just to the left of the stepper motor.
There is a sticky on the top of the Discovery forum main page with a "how to" on t-body cleaning.

 

the hose that goes from the throttle to the T-pipe for the cruise control is totally off, could that also be an issue or is that strictly for cruise control, any pics where the stepper motor or Idle control valve is located, i found out but not sure if thats it.