I've been having idle problems with my 04' Mini Cooper. This problem has been going on for over a year but now has got to the point where it's slipping into limp mode sometimes and I get the EML light. I took it to the mini dealer this past month and they said the problem was probably a clogged int. filter. ha right.... needless to say that didn't fix the problem. The dealer then changed all plugs, wires etc. and did a complete service oil etc and sent me on my way. Only for the problem to continue. So I was doing a little research and saw that it could be a clogged fuel filter or bad pump. So I replaced both because the car has 128,459 miles on it already. Then after replacing both the problem still is there. It will run like new then after I come out of a store it will start and idel high, low ,high, low, then when I shift into gear shutters and stalls. I am noticing that there is a chirping squeaking noise from the right rear fender but its not there all the time. I dont know where to look now or to start. I scanned an the only trouble code I have ever got was 0442, and I know my gas cap is sealing tight. Any suggestions?

 

What type of gas do you use?

 

Find what is causing the code....I haven't looked it up...
Sounds like you might have a bit of a vacuum leak...or a sensor issue...
On the positive side, your car does have a bunch of new parts, so once this issue is fixed, it should be a great car again for quite a few miles. Most of the stuff you mentioned should be done on a regular basis, especially once a car is getting up there in age, so no big deal.

EDIT:P0442 Evaporative Emission System Leak Detected (small leak)

 

evilness, I have been using mid grade 89 octane.

ZippyNH, I hadn't thought about vacume leaks and since the car's throwing that P0442 code maybe they are related. Do you have any suggestions on where to look for the leaks though. As for sensors, I was going to buy a new MAP and temp sensor too, but would rather see if I have any vacume leaks first. Hope I get it figured out. The car runs like a dream then will just start to irratically idel and stall out.

Thank you all for your input, and I will report on how it goes.

 

It could be a leak as zippy stated and it could be as silly as the Mid Grade / Bad gas you may be putting in your car as well. It's recommended 91+ Octane in the user manual.

 

The Evoprative emissions system uses vacuum from the motor, with a check-valve, I believe, to keep the tank under a slight vacuum, to keep the VOC's from the fuel contained. A leak with the system may be a contributing factor...it could be anything from a disconnected, cracked or torn vacume line, to a gas-cap with a bad gasket, that does not seal.
I honestly don't know if a leak in this system could make your car run rough, but it is throwing a code.
Would caution you against just buying random parts, and throwing that at your car....the basic stuff has already been replaced as needed for the miles...coil, plugs, wires...fuel filter was a bit of a long shoot, but it was likely needed after so many miles too, so good thing to get out of the way!
The Octane fuel you are using is pretty close to spec (89 VS 91)...likely OK, but anything is possible. It might be worth paying for an hour or two of diagnosis....
Swapping random parts without testing them on a modern car can get kinda $$ pretty fast in trying to track down an issues...so far you have done all the basic stuff that folks often overlook in maintenance, a good start. I'm sorry to hear a dealer was quick to diaganose an issue (and do it wrongly), but sometimes an issue needs to get a bit worse or more frequent to be able to track it down...it sounds like it is doing it a bit more often...so a shop might be able to replicate it, and track the issue down.

 

I think I just found the problem, I was checking the PCV valve, and the vacuum line coming from it that goes infront of the engine under the intake. I noticed it was a little loose and come to find it has snapped in half. So Im pretty sure this is where my vacuum leak is. Im going to run to get some rubber vacuum hose in the morning and fix it up. Im crossing my fingers this will fix my problem though.