Q&A

Although I am located in Toronto, Canada, it would appear that I have a similar problem to other queries.
On May 22, 2012, 104,000 km service performed (actual mileage 103,206)by an independent garage. Engine light on June 5th; computer advised problem due to code EVAP. Gas cap tightened, system reset; light off.
Thereafter, I have returned 4 times (gas cap seal reversed, rust removed from gas tank intake,and finally, a new gas cap was purchased). Invariably, the engine light would come on again 2 to 3 days after refueling. However, the last time the light came on was 2 days after the system had been reset. I am now being advised to go to a Toyota dealership and that I may be facing a bill of $3 - $400.00.
Was also advised to simply ignore the engine light being on; but of course this may eventually mask another problem.
Before consulting a Toyota dealership, I would appreciate any and all advise inasmuch as I was once advised by a dealership that the clutch was leaking oil and that the repair was urgent. A second opinion was sought; no problem found and I drove the car for another three years without any oil leaking from the clutch.