I have a 2005 2.5 with around 252,000 miles on it. I've had it for quite a while, but now it's my "backup car" and not often used. However, my 2010 X3 was having some work done to it and I've been driving it for three weeks or so.

My 2010 is done and I was driving the '05 back to where I store it when it stalled twice. It started right back up. More concerning though, was that when I got it back to the warehouse, I smelled rubber burning and when opening the hood could see some smoke coming from the right (passenger) front of the engine compartment. It was definitely a rubber smell and not oil, electrical, or coolant. All the belts look good and nothing (i.e. A/C compressor) is seized. It has not set off the CEL. I didn't have a scan tool with me to check for any pending codes

Does anyone have any ideas?