Soft "thud" sound at startup

[huyatgr]

I know this has been addressed before but I tried searching for the topic but I can't find what I'm looking for.

When I start my car, theres this soft "thud" sound every few seconds coming from the engine. I was sitting in my car outside the house with the car in park, waiting for someone today. The car starts out around 1k rpm and slowly goes down over time while making this sound. Once I start driving it stops doing it or I just don't notice it. I know when I first got the car at the welt, it didn't do this. It did happen later on in Europe but I largely ignored because I remembered reading it was something related to fuel valves opening and closing?

I'll ask my dealer when I go in to get my tags but any advice would be appreciated.

[Jack Dabsy]

Was it a "Thud" or a heavy "Gasp"? No solenoid or mechanical device should do this on a BMW... The only slight "thud" you should get is from the auto-box engaging, never in neutral !!!