I have a recurring (P0455 -- evap system leak) code and I'm very hopeful that a new gas cap will fix it. A few questions: 1)any way of knowing *exactly* what this code is pointing to? ...like gas cap, or could this be related to a leak in any of the miles of hose/tubing under the hood ? 2) do any of these Check Engine triggers reset themselves (like in the case of fixing the leak with a new gas cap), or can I look forward to two more twenties, even after fixing the problem, to turn the CE light off and appease my potential buyers ?

finally, my mechanic described a pressurization/smoke test of some kind, which he didn't have the equipment for, which allows them to find the leaky hose. It doesn't sound very high-tech, but am I going to find this test only at the V dealers in town ?

thank you.