Start-up revving

My '89 XJ with a 5 speed on a 4.0 revs to 1500 or 2000 rpm when it is first started. It happens hot or cold but only occurs for a second or two. No, my foot's not on the gas. I'm only worried because the oil pressure light doesn't go out until the revs are dropping back to idle. It runs and idles fine otherwise. Is this normal for Renix systems? I haven't checked anything yet but wonder about the TPS adjustment. Any ideas?

my 87 does that sometimes. It revs high for about a second. I'm guessing it's normal. That's the least of my worries right now though, i'm dealing with some electrical demons.

Supposed to be the reason they usually turn over 5-7 revolutions of the starter is to help with oiling, Have also heard the ECU requires a certain number of rev´s to function.
It´s supposed to rev to 1500 then settle in after a few seconds or so.
Occasional reving to over 2000, seems to be a problem, nobody I know of has cured yet (including the engineers at Jeep).

My 90 just started doin it recently. First time it did it I was a little scared it wouldn't go back down but it did right away. Mine started after I adjusted the TPS.

I've had this on and off for several years. You need to clean the housing of the idle air control motor/valve and the conical tip of the valve/motor. (Use carburator or throttle body cleaner spray.) The thing is supposed to move in and out of a cylinder in the housing to control the air bypassing the throttle plate at idle and during deceleration.
This housing and motor tip get gummed up with carbon deposits preventing the motor from moving easily.

I removed the throttle body to be able to remove that little housing.
Be careful with the screws holding the housing. They can snap. I used some WD-40 on the threads after I was able to loosen it a turn to ease in removal.

After this, the engine no longer revs high at start up and the idle doesn't stumble when I come to a stop.

MAP