Car idling low; engine going dead.

[jrdn]

A little background: About eight months ago, when I first bought the car, every once in a while the check engine light would come on after remaining stopped at a stop light for extended periods of time; and go away as soon as I give it some gas. When it got very cold sometimes, the check engine light would be on the car would feel weird.

The Problem: For the past few months, this problem has gotten significantly worse. It is now to the point, that every time I am stopped, the RPMs drop below 500, the check engine light comes on (followed by what feels like the engine 'dropping' or shaking), and the car dies shortly after. The colder it it, the worse this gets. The only temporary relief I have found is to drive the car for extended periods of time without dropping the RPM (e.g. freeway driving) and revving the car when it is stopped to prevent the RPMs to drop. I used to get an engine code 1222 (lamba control) and now I get 1231 (Battery Voltage/DME Main Relay), or 1213 (lamba control 1), I'll have to double check. My mechanic told me he thinks it could be the exhaust manifold or oxygen sensors, but I'd like an opinion from the board as he doesn't specialize in BMWs.

What is wrong? I have no idea where to even start, any help or suggestions would be appreciated:help

[pennpen]

clean your idle control valve (pita to get to), if nothing then adjust your idle so its a bit higher

[casesection8]

http://forums.bimmerforums.com/forum/showthread.php?t=1606697

a little check list for general idle problems. you might have sensor problems or a severe air/vacuum leak.

a good place to start in my opinion would be to check your battery voltage when car is running. if its too high or too low you can get some funky feedback from the electronics in your car.

what i would do:
-check battery voltage
-reset fault codes
-check connections, and if necessary replace both oxygen sensors.
-check connections and operation of MAF, ICV, and TPS.
-read fault codes

[HlyDvlz1989]

do the ICV first, its pretty painless to get to -.- pennpen

[pennpen]

ooo m60 i thought m50 for some reason lol, it was 4am :D

[mandd]

Have the fault codes read

Could be.....

Intake gaskets, throttle housing gasket and rear cover (CV).

Failing MAF.

Mark.