I've had my check engine light come on sporadically several times over the last year or two and each time the dealership claimed it was a loose gas cap. Given the frequency of the problem, I had them check it out a bit further and they pinpointed a faulty Evap Canister Valve (or VALVE,EVAP CSTR as it is written on the invoice). They wanted to charge me a pretty penny for installation, so I opted to buy the part and install it myself.
Thus the question - where is it? It seems like a fairly simple part to install - 3 connections - but I have to find it first.