anybody out there has any ideas on why the idling of my car is erratic. When the car is in P or N, the idle shoots up to about 1500 rpm and when in gear around 1000 rpm. I think that this is unusually high.

A couple of observations:
- there seems to a strong smell of gas inside the car
- my full tank mileage is around 250 miles ...........

I would appreciate any comments from any body that might have experienced this or an expert with this topic.