AutoNation Chevrolet Mesa

My 2018 Equinox experienced a failure mode that put the engine into a "reduced power" operation and set a check-engine light. My OnStar diagnostic was a restricted intake air that required immediate attention, which to me means to take it to a dealership right away. I called Autonation Chevrolet in Mesa, AZ as the nearest dealer. After an unreasonable amount of time, they concluded that the problem was with the intercooler for the turbocharger, and blamed it on using an aftermarket part when the vehicle was repaired following an accident a couple of months ago . But the intercooler was actually an OEM part from GM that should have been covered under warranty. Autonation wanted to charge me $667 in labor to install a warrantied part, (that's $136/hour!). Then when I refused to give them the job, they charged me $277 for the diagnosis, which they probably turned in as a warranty claim to GM after all. then the diagnosis that I paid for is still incorrect, because it shows an aftermarket part being used. turns out that the OEM part was improperly manufactured and should have been warrantied including labor.