Great group of guys working there. I have had a hard start issue on my Tahoe and of course it was not acting up when I took it in. So, they asked if they could keep it over the weekend to see if it would act up on Monday which it did. They tested the starter, alternator and battery where the battery was showing weak. They could not positively say for sure that was the problem but we replaced the battery.
Unfortunately I have had another slow start so I know what it is not. At some point I will take it back in because those guys did go the extra mile to try to figure out what might be the problem. They keep you updated as they work on your car.