2000 Buick Lesabre strong smell

Would you say it might be raw fuel smell? Moldy? Exhaust -like?....I can't quite get the whiff from here...

gasoline or oil smell

IT would be best to get the car up in the air and get a look at the fuel lines. They can get pretty rotted and allow fuel to seap through the line and cause a raw fuel smell. Typical areas are along the frame rail where othe lines are grouped and fastened together and also from the top of the tank where the sending unit is.

By racing the engine, fuel suction becomes stronger and circulates the fuel enough to reduce the leakage.

I would not put this off as the vapors are explosive. We had 2 shops in the last 2 years blow up from fuel vapors ignitiing.