Hi there.. since two days I started smelling some "fresh" gas smell near the front driver side.. and it's so noticeable only when I'm idling..
I started to play around under the hood.. Then I saw the below hose has been completely disconnected .. I reconnected it back in.. so far so good, I don't smell any fuel smell.
But this hose purpose remains a mystery haha .. so what does it do? and I can see that I can control that green plastic nut (tightening or loosening it)..

 

That's your fuel vapor feed hose #2...

 

Hmmm.. so maybe that's why the smell stopped popping up..
But out of curiosity do you have any idea what does this green nut do?

Thank you so much for your help..

 

The green plastic part (77739-33010) is called Evaporative Service Port Valve. Take a look at the Youtube video (it's not mine!) for details on its use...

 

Will look into that.. many thanks!

 

While trying to track down a fuel smell that has been going on now for years, the area you have circled connecting to the green cap consists of a number of vapor hoses which over time get brittle. We tried smoking the system but found nothing. I changed every single one of those, including the line going to the PCV valve. Every little hose was hard as a rock, It was difficult disconnecting them because they were practically cemented to the plastic joints in between them. I needed a sharp razor to cut them off. I got all the OEM parts from Lexus and replaced everything. Smell still there, but all my hoses are fresh.

 

from another previous threads I can see it's usually an issue in the fuel dampers. did you try to replace them? also try to remove the engine plastic cover and set the car idle for like 15 minutes just to ensure that the smell will start to come out...then begin the smelling game... maybe it's one of the injectors O-rings.. I hope.
Actually I don't trust mine yet... maybe that disconnected vapor hose wasn't the culprit and smell will come back again .. let's wait and see!

 

Dampers are fine as well as injectors, injector seals and just about the entire fuel injection system. I have the notorious PO440 code along with the gas smell, so all things considered, the emissions evaporative system needs further investigation........and it just happens to be one of the most difficult systems to find the actual fault. My luck!

 

Hello all. I own an 04 base model and have noticed a misfire and a noise coming from the rear of the engine and while searching for the sound I noticed this hose and become so old and brittle that it just snapped on one side of the T. My question is could this vapor hose cause the misfire and sound I hear? I've also noticed as the car is aged many of the other hoses hard and brittle the same way. Is this a normal thing?

 

If you live somewhere HOT and dry (like Texas) then your rubber parts will age at an accelerated rate.
It is the price you pay for not having to deal with rust <LOL>
I think you need to start budgeting for replacement hoses and the plastic parts that some of them connect to, as heat also makes plastics go brittle.

Here in the UK where it is wetter and much cooler, the rubber parts will sometimes outlast the car.
In my 20 year old 2004 with 145k miles all of those hoses are still supple and flexible.
The coolant hoses will need replacing soon, but will get that done when she goes in for the timing belt/water pump/radiator/thermostat work.