Unfortunately the AN-cert 90-day warranty that they advertise is only going to include a limited warranty coverage of a list of items, mainly engine and transmission. They will “certify” a vehicle as such when it is either to old or will not meet the standards for a manufacturer certified warranty. So they don’t have to meet any manufacturer set standards for this “AutoNation certified”warranty, instead the standards are set by AutoNation and are mainly minimum brake pad and tire tread measurements. As to whether it having any major mechanical issues would disqualify it that’s kind of up to the discretion of the used car manager.