My wife's Chery SUV, when going down steep gradient will slow down by itself, considered fuel cut?
Hard to say. You can try going down the steep gradient either hold 2nd or 3rd gear make sure A/C comp. is off. Then look at the engine rpm. If it has fuel cut, when you shut the throttle above 2.5k rpm, then rpm will drop, then let it drop by itself until 1000rpm. If any where in between you need the needle jump up the fuel has come back on you mighht feel a slight nudge forward. If its smooth all the way to 1000rpm it has no fuel cut.
Usually they will cut fuel until 1200rpm (a/c off) with a/c on it will cut fuel until 1500rpm. So in either situation when the needle drops to 1200 rpm it will shoot up to 1300-1400rpm again.
But if you don't find fuel cut in you auto don't worry, not a very common feature in autos but some of them do have it. They usually don't have fuel cut in auto because they want to smoothen the drive and most of the time people leave it in "D" and the car will upshift to the higher gear when you off the throttle and cruise which usually drops the rpm to a range which is not always suitable for fuel cut and if it does, its for such a short time that hey don't bother.
This feature is best for manuals and if you know how to make full use of it, other wise you're not gonna save much.