Unless a code is thrown, it is very difficult to diagnose correctly gas smells or emission control system issues. Although I have had a gas smell for years in my car I finally had the check engine light come on with P0440 and with my gas smell helps me at least go in the direction of the charcoal canister and all of its constituents including the purge valve, the VSV, and the vapor pressure sensor. Throwing parts at a symptom can be costly, frustrating, and of course a waste of time. I'll have my Indie take a look initially, and if too difficult, I'll take it to Lexus and although I'll probably be taken over the coals....I might have a better chance of getting to the exact problem. FYI, in addition to my car smelling from gas after every trip, my gas mileage stinks (12-13 all city) yet the car performs and idles like a new car.

 

I had a gasoline smell and my boyfriend found a bad "fuel damper" at the top of the engine drivers side against the firewall. 1" round part with screw in top. New $65.00 damper, problem solved. Hope this helps.

 

Was your gasoline smell in the cabin, or outside the vehicle?

 

 

My vapor smell is from the outside near the rear after shutting car off. I also get the PO440 code for years now. Attempting a fix can be frustrating as well as costly. After various smoke tests, replacing all vacuum lines plus more I gave up. Since the performance of my car has not been affected I'm ok with it. If I lived in California it would be another story. . FYI.....The LS430 is known for vehicle emission CEL issues.

 

is your vehicle garaged?

Probably the issue will not improve with time.

It wouldn't be wrong to replace certain tank seals and hoses...

 

Everything close to the canister is buried under the tank and above the rear axle. Not easy to get to. Yes my car is garaged and the smell is not always there and also not at all overwhelming.