Strong fuel odor driving up hill-Help!-

[kims bimmer]

My family's 2005 BMW 525i-automatic trans. 60k miles-has a problem that the dealer is having a hard time diagnosing(we have an extended warranty).For the last 8 months every time we go to San Diego from Arizona (4 round trips) we have to drive up a 6% grade for about 7 miles, when we are about half way there our car reeks of raw gasoline, so much so you must roll down all the windows or you will asphyxiate-it is really strong! Not only is this uncomfortable this is most likely dangerous. This also happens on the way back home. About 15 minutes after the car levels off or starts going down hill the smell goes away. It doesn't happen when driving on level roads and it takes about 10 to 15 minutes of incline driving to occur. The tank is usually at 3/4 or less. The dealer has not found any leaks or any problems, and I highly doubt that they will take the time and effort to drive it up an incline for a length of time. This car was purchased in California new, so maybe it is an emissions problem?
Thanks for reading this, any help is appreciated.

[darkhorse737]

...am very surprised why your dealer hasn't done a smoke test on your vehicle.

It only takes a max of 5mins to smoke the tank of your car, and from there, he'll be able to define(visually see...) where the leak is.

i dunno how your shops do the workz... but i would try to replicate the conditions that you describe when the faults occur... i.e. lift the front wheels to an incline that say it happens and run the engine. That isn't hard to do for any shop tht has a lifter.

ay-yay-yay!....