about four liters if you just do an oil change. This varies because when changing the oil, it never drains completely - some oil remains in the torque converter.... For both other problems, check for air leaks as your engine may draw air that is not measured by the MAF. Also check the idle stabilizer valve and clean it when necessary, although ISV trouble tends to manifest itself mainly at cold starts. The CAT lamp only listens to a heat sensor placed in the cat and should light up only when the CATs are getting too hot. This could well be the result of an air leak after the MAF, resulting in a lean mixture and hotter-than normal combustion temperatures, wich may explain the "attention, too hot" CAT lamp coming on.
