E39 2001 520 AUTO STARTING FAULT - AND STALLING?

I HAVE BOUGHT A USED 520 TOURING, 2.2. AUTO WITH LOW MILEAGE - 39K
IT HAD OLD REPAIRED FRONT END DAMAGE, BUT ALL SEEMS OK.
IT HAS AN OCCASIONAL FAULT WHICH IS DRIVING ME INSANE.

EVERY NOW AND AGAIN, PERHAPS ONE IN 20 STARTS FAILS UNLESS I PRESS THE ACCELERATOR PEDAL. THE STARTER MOTOR IS TURNING WITH FULL POWER FOR 3-5 SECONDS WITH NO FIRING UNTIL I SQUEEZE THE THROTTLE. THIS NEVER SEEMS TO HAPPEN FROM COLD AND IS TOTALLY UNPREDICTABLE AND COMES WITHOUT WARNING OF ANY SORT.

COUPLED WITH THIS, A RARER ISSUE ARISES WHEN PERFORMING LOW SPEED MANOUVRES - THE CAR JUSTS LOSES POWER AND STALLS. I HAVE BEEN PRESSING ON THE THROTTLE TO GO BUT NOTHING. - IT THEN HAS THE START FAULT AS ABOVE AND GOES BACK TO NORMAL. THIS HAS HAPPENED LESS THAN ONCE A WEEK. CAR HAS JUST BEEN SERVICED, BATTERY IS OK, I SUSPECT I MAY HAVE A FUEL MANAGEMENT / DELIVERY ISSUE, BUT DON'T KNOW WHERE TO START.

Hi there, Sorry for the late response!...

it sounds like a cam sensor. They tend to go intemittently faulty rather than completely fail. This would cause random cutouts. I recommend getting the fault codes read, it is cheap to have done and most independant garages stock the readers, and this should give you the answer.

hope this helps.
mightybmw.

Thanks for your help, local mechanic found a cam sensor fault code, but had never had to repair one before, I'm told it may have 2 sensors;
1. Are there 2?
2. how do I know which one is faulty?
3. have you any pics that would help me locate them?
4. are they both the same replacement part?

Thanks

Ow

Have a look on here it will show how many you have along with the location and part numbers.

http://bmwfans.info/parts/catalog/