My car is running very strong and I love it! I was able to pull 234whp and the tunner believes there is still more, but I do have one problem now. When I have the A/C off my car drives perfect, smooth and pulls hard, but when I have the A/C ON and come to a stop light or even if my revs drop too fast the car will go into LIMP mode. The car makes a lump feeling, the EML comes on and I can't go faster than 4mph. All I have to do to fix this problem is to flicker the key and everything goes back to normal. Sometimes at stoplights I keep the RPM above 1200 and that keeps the car from going into LIMP mode.
I think the code is 1684P that comes up. I'm thinking this is a very small Vacuum leak somewhere. I have taken it to many people but no one can fix it.
I really need some help
Thank you
Mario

 

I'm having somewhat a similar issue on my 2006 MC with coming to a stop and car going limp. It just turns off randomly. I am finding that it does more often when I drive a long distance--like on the highway--and then come to a stop light. The car just turns off. I get all the lights on because its the same as putting the key in the ignition and turning it to second position...all the lights flash on, but when the car starts they turn off. So I restart the car and all is well...lights go off, car runs fine. Dealer shows no error codes whatsoever.

Apparently there are a lot of mini's out there with this and similar random limp modes when coming to a stop.

Sorry I can be of no help, but at least you are getting an error code...I get nothing. When a dealer says there is nothing wrong, that stinks because there is technically nothing to fix in their eyes.