Any mods to your Vette?I'm getting the EXACT same thing out of the blue for the past week. Usually happens ONLY a few minutes after starting her up and idling around the streets.
Car isn't even at full operating temps when this does occur which leads me to believe it may have something to do with the O2 sensor ???
I've cleared the codes 3-4 times now over the past week and a half and the SAME TWO codes P0171H and P0174 keep coming back. Sometimes one at a time and other times both at the same time. :huh: