I have a 2005 545i, what a great vehicle! However, when the vehicle warms up and is at idle it shuts off. Everytime I come to a traffic light or stop sign, I have to keep my foot on the brake and gas at the same time or it will shut off.

Has anyone had the same problem, if so, what can it be?

 

vacuum leak?

 

Where do you think the leak is coming from?

 

Are you getting check engine light? How many miles on the car?

I would also suspect vacuum leak or MAF sensor

Vacuum leaks can develop in few places

http://realoem.com/bmw/showparts.do?...59&hg=11&fg=15

or at pressure regulating valves (part 13) - on 545i you should replace them every 50k miles (as preventive maintenance)

http://realoem.com/bmw/showparts.do?...58&hg=11&fg=15

 

Marcellus545, your vehicle should run even without the Mass Air Flow Sensor being connected. It will choke but it should at the very least run. The PRVs as are a common part that fail on your vehicle. You have two of them and BMW is aware of this so they are a very cheap part. I think they are around $11 each for me when BMW delivers them if I'm not mistaken. Have you done any maintenance on this car recently? Is your car showing any faults? Do you have a reader?

 

Thank you everyone with your assistance in this matter. I replaced the PRV's and found a rip in one. My baby runs good again.