What car is it? Does it smell inside the car or only under the hood? Does it only smell with the car running or all the time?

Year, model, etc would help.
Without this information I can tell you to check the following.

Rubber fuel lines -- check with the car running as they could have a pinhole.
Idle control valve
Charcoal canister
Fuel injector lines

If the car has a carburetor
Check the base for leaks as well as the float reservoir
Check the intake manifold for leaks.


Good luck

__________________
"I have no convictions ... I blow with the wind, and the prevailing wind happens to be from Vichy"

Current
Monika '74 450 SL
BrownHilda '79 280SL
FoxyCleopatra '99 Chevy Suburban
Scarlett 2014 Jeep Cherokee
Krystal 2004 Volvo S60
Gone
'74 Jeep CJ5
'97 Jeep ZJ Laredo
Rudolf ‘86 300SDL
Bruno '81 300SD
Fritzi '84 BMW
'92 Subaru
'96 Impala SS
'71 Buick GS conv
'67 GTO conv
'63 Corvair conv
'57 Nomad