I have a 2002 182, and also experience a faster draw rate from one tank (I think the left).
Anyway, was talking with my A&P this wknd, and he had read an article about the subject. Seems that if you view the plane from the front, it is apparent that the vents are not positioned equally relative to the wing struts. One of the vents is more behind the wing strut than the other. This results in different wind/air pressure at the vent, thus a different draw rate.
I can see the difference on my plane. Maybe that's the cause, maybe not. In any event, I have decided to leave as is for now.
Steve

I believe this behavior is common to many Cessnas, especially those with long range tanks.  I've noticed that my 182 is often a gallon or two lower in the left tank than the right.  The way the vent system is designed, fuel can siphon from the left tank to the right through the vent crossover when both tanks are full and will continue to do so for some time because there is so little dihedral in wings.  Since only the left tank is vented to the atmosphere, there is more pressure there than in the right.  You might check the positioning of the vent tube relative to the strut also.  I think Cessna issued a SB about this some time ago and the positioning is critical - just a tenth of an inch lower or higher makes a difference.