GMC dealer has been working on this problem for 17 months. This last time the dealership had it for five weeks, sitting in their shop. Total number of times it was in the shop has been seven times. The service department at the dealership has done everything the tech support has suggested at the GMC tech support department. The regional person over this region tells me there is no problem, that the vehicle has not been driven enough in this hot humid environment. Interesting thing is that when it was new had had very low mileage there was not a problem. I actually have no idea how many weeks the vehicle has sat in the shop not being driven. Maybe my mileage is lower than they think it should be because of that. But the answer they gave is pretty ridiculous to me as well as the people I have told about it. As well my wife's Toyota has about the same number miles per year as the Envision and we do not have a problem with it. I have talked with many people here in south GA and they have never heard of such an excuse. We lived in south FL for 15 years and never had such a problem in that hot humid environment. Guess the big corporate environment is not concerned with us little guys who spent hard earned money on a brand new vehicle that they made.