Next time your grill is just sitting idle on a sunny day turn it on and look at the thermocoupler reading. I'll bet that at 83* outside on a sunny day you're looking at close to 100 internal temp. That makes for just a 65* increase in temp to get to 165, which it looks like the grill is not built to do. Mine sits around 220 when set at 165 on those days.
My thoughts almost exactly... I would deem it quite unlikely that you could start a fire burning inside a box that's already 100*+ and ONLY raise it and maintain 65 more degrees??? That's why I took my Pro22 back because the 'smoke' settings was supposed to keep things right at 165, it was at 250 for 45 minutes and never went down... (Plus I really wanted to upgrade to the Wifire anyway)