Been battling a check engine light for 6 months now. Small and large evap leak. Changed the gas cap. Light stayed out for a few weeks so I went to emissions test. Failed. System not ready. Two tests incomplete. Didn't fix it. Got fed up and took it to the dealer. Dealer does a smoke test and pressure or vacuum test, whatever they do, and come back with everything is holding. Can't find anything wrong. "Might be the vent valve/solenoid". How much? "$400". Uggg. Sorry I'm not replacing parts on a guess at $400. Took it home. Been driving seven days, highway, city, idling, overnight, in garage, outside garage, almost 400 miles. Eight tests ready, EVAP test incomplete. That is complete BS. Decided to change the vent valve/solenoid myself today for $69. Test still incomplete. Very frustrating to say the least.

On a side note, while changing the valve, discovered that the body is starting to rust out in may places but primarily at the welds and seams. Again pretty discouraging. A nice 2009 Hummer with 67,000 miles turning into a complete rust bucket thanks to the moronic DOTs pouring highly corrosive chemicals all over the roads all winter. That and insufficient corrosion protection on the vehicle.

I am so tired of GM products.