Mine does not make any such noise and my garage is not heated at all. What ever the temp is outside, that is the temp inside. Even when it is -20 F and it is not plugged in, my V6 does not make that noise. It does high idle for a bit, as is expected, but no noise like that.
Sorry some of you are having issues.
2015 Trailhawk - Eco Green, 3.2L, Nav, Tow, Cold Weather. MODS: Goodyear Wrangler All-Terrain ProGrades 245/70R17; WeatherTech mats, vent shades; Magnaflow exhaust. Rigid SR 20" bar and Rock Lights. JW Speaker fog lights. Blue Ridge Overland Gear panels and bags. Pelican tool box loaded! Bubba Rope and Gators too. Much more....
Trailer: Custom built Montrose aluminum 4.5'Wx6'Lx3'H off-road utility with 3,500 lb Dexter torsion axle. Known as the Zombie Escape Trailer.