Clanking sound after I shut off the car

[AZ190E]

I have a clanking sound after I shut off the car - 91 190E 2.6.

It sounds like coins rattling around in a tin can, and it appears as if it is coming from underneath (or deep within) the car. It is almost like it is still trying to run, but not spitting or coughing, just clanking.

I also have a fuel smell often, and a shop that looked at it recently said that I might have a "smog pump" bearing needing replaced, but then just concluded that I have the wrong kind of belt, which is making some noise.

I thought it may be a rock rattling around in the exhuast somewhere, but it sounds more like and engine problem.

I am a new owner and would appreciate any input.

AZ