Have a GMC Jimmy 5.7 ltr. injection (normal gasoline) for a little while and it is in a well-kept condition, but some defects are not worth mentioning outside. But now I am a little confused by his thirst, because according to my calculations he has now consumed 20 ltr. on 56 km. Is that normal or utopian?His previous owner allegedly drove him with “14 ltr.”, I then expected 20 ltr., but 40 ltr. is tank-like or is that normal?