Okay so I have a 2002 mini cooper S and I've been chasing this problem for about a year on and off. If I got to a drive-thru, almost every time while I'm waiting, my idle will begin to fluctuate and almost stall. I am also seeing a p2096 which I originally thought was due to my cat delete(I have a defouler that worked for about a year, then this code popped up) but this idle issue has been going on ever since I've owned the car. I talked to a few people on here who suggested it might be caused by a vacuum leak. So I went out this morning and sprayed the engine compartment with water/brake cleaner(although I wouldn't recommend spraying flammable liquids into your engine bay, this is how I found something) and I sprayed next to the air box right underneath the positive battery post, and my idle started dropping dramatically almost stalling. I tested this three times in a row to make sure it wasn't a fluke. After I was sure, I grabbed a flashlight to inspect, started the car back up, and after spraying again, nothing. So I'm wondering if there is a vacuum line in that area that may only be open at certain cycles of the ecu? like the purge valve? But as far as I can see the only vacuum line over there is for the brake booster. I'll attach a photo of where I was finding this leak. IF anyone has any ideas PLEASE let me know. This has been plaguing me for years! Thanks!


the line I'm touching is the only line I clearly see(I sprayed the fitting like crazy and didn't get any Idle issue after I restarted)

 

I'd also like to add that my Long term fuel trim was around 16% which i think would indicate there is infact a vacuum leak somewhere.

 

Update: Just did a diy smoke test, couldnt find any smoke coming from the location described above, but i did find there is a leak coming from under the throttle body/super charger horn. I believe its coming from that housing with the two plastic hoses going into it that have the red collar connectors. Tomorrow ill Pull it apart to look closer and see whats going on.

 

Update: Repaired the vacuum leak which was the Map Sensor hose that goes to the super charger intake duct. i was able to get to it by removing the throttle body and super charger horn. But sadly, still getting the p2096. So i guess i search for more. IF anyone has any suggestions please drop a comment, thanks.

 

have you looked up the mini code for 2096, I’ve forgotten what it is. Also what is the description for p2096?

have an r53 where new tmap cleared up lean condition and intermittent rough idle

have an r50 where a new cam sensor and O2 sensor cleared up lean condition and stalling when AC compressor would turn on. O2 cleared lean condition (or was it rich?) and cam cleared stalling

 

Do you have a leak in your exhaust? Has your secondary cat broken, or cracked? That can cause a exhaust leak inbetween the primary and secondary O2 sensor which can throw the code as well.

 

Good to know! maybe ill bite the bullet and order a new tmap. ill look into the cam sensor as well!

 

i expected to find a leak but unfortunately, i didnt find any exhaust leaks. It all looks nice and tight. And as i mentioned in my post i no longer have a cat in the car. today i tested what would happen if i moved the sensor back into the exhaust rather than into the defouler. This removed the lean code and gave me a p0420 code which was to be expected. So it looks like the cause may just be due to the defouler being too long. so maybe ill order a shorter one and try it out.