M3 motor problems. VANOS? ICV?

I have been having a very weird and interesting issue with my 04' M3 SMG. My car has been having idle and stalling issues. The codes that have been read are all pertaining to the exhaust camshaft and the exhaust pulse generator (fancy Camshaft Position Sensor). I did replace the exhaust sensor but the codes still persist (its been about 500 miles) as well as the idle and stall issues. But here is where things get interesting. Every time I turn on the engine, it responds differently. Sometimes it will hesitate, sometimes it will not turn on at all, and others it will turn on perfectly fine and run strong. I have realized I can somehow control this with having different things turned on in the car (as weird as that may seem). Sometimes, it will turn on, and function, correctly if when starting the car, sport mode is on or the air conditioner is on or any combination of the above or, of course, when there is nothing on. Its a very odd situation. I have a couple verdicts in mind; The ICV, Vanos Solenoid, Exhaust Cam Hub, faulty Exhaust Cam Sensor. I'm not very sure what I should do at this point. If any of you have any suggestions or possible diagnosis it would be great. Thanks

What is the age and state of your battery?

Oh, did you reset the codes after replacing the sensor?

The battery has never been replaced so about 10yrs and in not sure what you mean by state. And yes the codes were erased but returned

What I mean by state is, is it fully charged and healthy? At 10 years old, you're at least 3 years past due for a new one. Weird stuff happens when the battery isn't healthy. See M3 story in this post:

http://www.bimmerfest.com/forums/sho...32&postcount=4

And no, you do not have to buy an expensive BMW battery. See the WIKI for affordable alternatives.

Start there, reset the codes again, and see if they return.

Sounds good. I just don't understand what's happening. Hopefully that will fix it.

Originally Posted by Drvidal1

Sounds good. I just don't understand what's happening. Hopefully that will fix it.

By all "normal" standards, your car should be on it`s THIRD battery by now. Send the current one off to The Smithsonian before it destroys the alternator as well, and adds to your repair bill !

Haha top of priority list now!