2000 Toyota Sienna Gas Smell

We have a strong gasoline odor inside the van, which seems to come from the vents. The Dealer checked it over, cleaned the carpets, did an ozone treatment, and checked out the engine. They could not find a problem, and say there are not any previously known problems of this nature with Siennas. A friend recommended a new gas cap, and that has helped some, but the smell still takes over… just not as strong, we think. The dealer’s next move would be an expensive proposition, so I am looking for anything to help short-cut to the real problem. Any ideas out there?

Thanks ahead for any replies.

did dealership look for any leaks in the filler tube or upper tank region? any gasoline leakage when you fill up?

Thanks for the reply - Yes, they checked the tank, and there is no leakage at any time.
Everything on the car is great besides this smelly problem. I have not noticed any difference in gas mileage either. I believe it is coming from the engine somehow because of the fumes entering from the blower, but I am not much of a mechanic…
Sure appreciate any other ideas.

I just bought a 98 Sienna with 115K miles with the exact same issue. Any new info on this problem? Have you contact Toyota Corp?

Many times a strong gas smell can be attributed to the charcoal canister or lines going to or coming from it. Sometimes it is hidden, but usually in the front part of the engine compartment. When a line or plastic connector cracks, or line becomes disconnected, the fuel fumes come straight into the engine compartment which gets sucked into the cabin, instead of the cannister which is suppose to contain/filter out the fumes. I’d start looking in that area.

Benny’s advice is spot-on, however I’d also suggest a smoke test of the EVAP system. That’s a test wherein the air-filled areas of the system are pumped full of smoke (with a smoke machine) and the smoke comes out any leaks.

The test’s limitation is that of the leak is in a wet area of the system the smoke test will not pick it up, but since you don’t mention any dripping or puddling the leak is probably in an air filled area.

See the responses after yours. I have not contacted Toyota myself, but the dealer checked for any bulletins that might have been put out, etc. I’m collecting ideas at this time before I go further. Today, we could not even smell it… I am hopeful about the new gas cap. Please stay in touch if you find anything out, and so will I.