OK, I have everybody, including the dealer, stumped on this one: I have a 99 M with 100k miles on it. About 3 weeks ago the local temperature got about 15 degrees F and it has remained that way or colder since. At the same time. I began to develop a problem where my car would just shut off on its own while I was driving. At first it would happen after doing about 15 minutes of city driving. Now it does it almost immediately. Car used to restart immediately, now it requires me to drive 2-footed to get it to start without stalling.

I initially had my spark plugs replaced and my throttle body serviced. Then, I had my crankcase and cam position sensors replaced. Then, I had the dealer find and fix a vacuum line leak. Then, I found and fixed a loose connection on the positive clamp going to my battery.

There have been no check engine lights or codes. The car seems to run more reliabley after driving it for a while, though my tach seems to be acting a little erratic (i.e., I take my foot off the accelerator while going up hill and rpm remain at 1500, jump up to 1750, then decrease to match speed).

The problem always occurs after the car has sat overnight in freezing temps.

I am getting ready to ditch this car. Any last minute suggestions?

 

I am having the same problem. Except I am in the south and the temperatures are mild. Also have the the erratic RPM jumps. I think my issue is with the fuel system but not sure. Does anyone out there have any other suggestions as to what the issue may be...

 

Check Fuel Pressure. There is a port, center, drivers side of plenum near the center coil. Pressure should be 50+ at all times running.
PCV valve how old ? Can stick intermittantly...