Oh, so it means that the owner forgot to prime the oil pump, there are still some air inside it causing high rpm.  He forgot to burp it.  

WRONG AGAIN!
This is what the original post says:

that car had already an existing mechanical problem even before the owner did the oil change..period!....don't put the blame on the oil change.

that's my assesment.

Hi all,
Thanks for your thoughts. They are really helping me to think better about this problema.
Today a recorded a video, to show you better the way the car is doing. Like i said before, when the car is cold, the rpm's are normal, but later , when in NEUTRAL, the RPM goes to 1500. And I noticed that when in NEUTRAL and moving, the rpm going up and down, like if they were adjusting (between 800 and 1200). The video shows the a normal rpm ( while dring in 4th gear, 2000), then put the car in NEUTRAL, while still moving, and you can see the rpm jumping between 800 and 1200), and then finally stopped at the traffic light, when it goes to a fixed value of about 1200 rpm.
And I already tried to disconnect the MAF, but the car stays with the exaclly same problem! So I should eliminate his cause, right? Someone was telling that the Mini has 2 MAF????
Another information, some weeks ago the car had a leak in the thermostatat housing.....but it was fixed at PepBoys,,,could it be something related with this? Before that it was just a minor leak and I was not that worried with that...
Thank you all

One of the simplest tricks is to disconnect the wire connection to the MAF and let the engine run on default settings. If it smooths out, then replace the MAF.

Some people disassemble it and clean it, but I personally prefer to just replace it now (rather than later)

This advice is from experiences with VWs, but BMW and other FI engines often respond to this same trick.

Here is a thought...  it may be an issue with the temperature sensor in the thermostat housing.  If the temp sensor tells the computer the engine is cold, the computer will richen the fuel mix as it should when the engine is cold.  As the engine warms up, a defective temp sensor can continue to cause the computer to run the engine too rich - thus causing the errors and fast idle.

Another clue is the temp sensor and thermostat housing is a 'known issue' for the 2009 model.

If you take it to the MINI dealer, and the issue is found to be the temp sensor - MINI may cover the cost of repairs since the temp sensor / thermostat housing is considered to be part of the emissions system where the warranty is 10 yrs.

Its difficult to accurately diagnose a problem remotely, this seems 'likely' but can say with 100% certainty.

ken

Like you, I know nothing about BINI engines, even their oil changes.
Are there sensors/wires or other components near the drain plug?
How difficult might it be to remove and replace the oil filter, any special tools or procedures needed, any sensors, wires or vacuum lines that might get disturbed?
Where is the filler - are there wires or vacuum lines that might get disturbed or affected by sloppy oil pouring?
Are there any special procedures to follow that may not have been done properly?
Was the technician doing the oil change poking around checking for other potential problems, leading to possible sale of additional services? When I have the oil changed at a good lube shop, they check belts, battery and connections, other fluids including window washer fluid, brake master, filters etc.
These 'questions' are rhetoric and hypothetical, so you don't need to try to answer any of them. (They may provide to the original poster some ideas to consider and rule out.)

Hi! Thanks for your thoughts! I already got the codes from Autozone:
P1150 NO DTC definition found
P2178 System too rich off idle Bank 1
P2187 too lean at idle bank 1 ( I might have the code description bad on this one, and I am sorry, but they only gave me a handwritten paper)!
Any new thought? 
I found something interesting....as I told before, when the car is cold, the rpm are normal, around 800rpm, but when it reaches the operating temperature, and at NEUTRAL it goes to 1500rpm. But now I discovered that when in NEUTRAL and the car is moving (lets say more than 20 mph), then the RPM are moving between 800 and 1300rpm (really moving, up  and down, continuously).
Any idea is welcome, and many thanks to all!

1. But dan, do you really think something can get “jarred” inside the engine when you do an oil change??????? Regardless of the engine?

I'm still trying to figure out what a mini copper is. Maybe one of these?

As usual, specialist did not read. The original poster has a new MINI, aka BINI from 2009. Ignore specialist.

something was jarred loose during the oil change??? What could it be other than the oil cap???

i suspect there are air pockets that got trapped inside the oil pump, you need to prine it.

this is based on experiences....not in the book

Hi all. Thanks for your messages. I am reading all of them very carefully, and I will post any change here. I had an error in my initial message, the mini is not from the year 2000, but from the year of 2009. Tomorrow I will read the codes in an Autozone store and I will publish them here. Thank you all.

It sounds like you have an early new MINI (BMW) - non-supercharged cooper (non-S) model.

If these symptoms started after an oil change, there is a good possibility that something was jarred loose during the oil change causing the symptoms.

First question - do you have any check engine lights?  If so, you need to have the codes read with an OBD code reader. in fact you might do this any way to see if there are any errors recorded in the cars computer light or no lights.  If there is an error code recorded - post it here.

Next thing is to look for any vacuum leaks.  The 'old school' method is to get a can of starter fluid or carburetor cleaner and spray near any of the intake pipes or vacuum lines to see if the idle changes - if the idle changes, you have a leak.

Your MINI has two MAF air flow sensors, one of them may be defective.

Check the electrical connection to the throttle body, make sure you have a solid connection.

These are some of the items that comes to mind.  There may be more but maybe this will help you eliminate some of the potential issues.

ken

The "non-turbo" wording is a bit confusing. No Minis built in 2000 had a turbo. Do you mean a 2001 or later BMW MINI Cooper?

Hi all, I have a 2000 Mini copper, non turbo, and after changing oil at 100k km, my car started to have high rpm in neutral. I had the car once in Pep Boys and I was told it would need an Mass Flow Sensor. They replaced by a new one, but the car did not improve, so they reinstall the old one at no charges. Later on I had the car at Mini, and they also told me the car would need a MAF, along with new spark plugs and coils, and they wanted to charge me a lot and I said no. After that I bought and installed new spark plugs, new coils and also a MAF, but the car remAins with the same problem.
When the motor is cold, the rpm are ok, around 700-800 rpm,  it when it warms up, it would go the the 1500-1600 rpm. Can someone give me some help on this? Thank you!