Hi all,
Hoping that someone may be able to help me with an issue that has just cropped up for me. While sitting in the car (cold outside) with the engine running to keep the heat up, the engine, after quite a while, like 15 or 20 minutes, starts to idle down and run pretty rough. If I don't give it the foot I feel that it might sputter out and die. The car is new to me for about a month. 2003 MINI Cooper S, 167k on the clock now. I just did the engine oil/filter service, air filter, and fuel filter. I usually run regular because it's cheapest (obviously) and I thought I read somewhere that MINI's were designed to run on it. Other than this issue the car runs pretty well, aside from the shot hubs that I'm hoping to replace this weekend.

Any thoughts are very welcome.

Tom

 

It could be more than a few things. Any check engine lights or any codes present in the system? When you drive it for a bit and come to a stop does it dip down again?

I believe that MINI indicates that you should use the highest octane available for better performance for the R53. Some good info here:

 

First of all, wrong gas. The gas cap even says 91 or greater. I doubt that that is your problem though. The motor management will retard the spark in attempts to keep the motor safe. Spend the extra $2.50 per tank and run the gas the motor was designed around.

Three things are needed for combustion. Fuel, air and spark.

Fuel-you have already changed the fuel filter so check that off the list. Dirty injectors? For $10, get a can or two of Sea Foam and add it to the tank. I have had good luck with this product. Others will chime in with their favorite. Other than that, fuel pump, pressure etc would need to be checked.

Air-This is my bet where you have issues. Air filter-check. Next I would be looking for cracked hoses. The car is old with lots of miles so a vacuum leak is very possible from one of the vacuum lines.

Spark-you haven't stated that you changed plugs so with 160,000+ miles, it's a must check or replace. Also look at wires and coil pack. The number 3 terminal tends to corrode.

This is only a start to trouble shooting your issue but all this falls into the realm of preventative maintenance so any money spent will not be wasted.